LINQ 基本知识

1.1泛型

目标：解决参数类型转换效率，利用泛型可以提高效率
using System;

namespace DemoGeneric1
{
    /// <summary>
    /// 泛型类
    /// </summary>
    public class GenericClass<T>
    {
        /// <summary>
        /// 泛型类型的字段
        /// </summary>
        private T value;

        /// <summary>
        /// 泛型类型的属性
        /// </summary>
        public T Value
        {
            get
            {
                return value;
            }
        }

        /// <summary>
        /// 带泛型参数的函数
        /// </summary>
        /// <param name="input"></param>
        public void Add(T input)
        {
            this.value = input;
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            //使用字符串类型
            GenericClass<string> str = new GenericClass<string>();
            str.Add("字符串测试");
            Console.WriteLine(string.Format("Value 类型：{0}", str.Value.GetType().Name));
            Console.WriteLine(string.Format("Value：{0}", str.Value));

            Console.WriteLine("******************************");

            //使用 int 类型
            GenericClass<int> intc = new GenericClass<int>();
            intc.Add(123456);
            Console.WriteLine(string.Format("Value 类型：{0}", intc.Value.GetType().Name));
            Console.WriteLine(string.Format("Value：{0}", intc.Value));


            Console.ReadKey();
        }
    }
}

1.2 Arraylist 和List<T>

using System;
using System.Collections.Generic;
using System.Collections;

namespace DemoGeneric2
{
    class Program
    {
        static void Main(string[] args)
        {
            ArrayList arr = new ArrayList();
            List<int> lst = new List<int>();

            //ArrayList 计时开始
            DateTime dt = DateTime.Now;

            //将100万个元素加入ArrayList
            for (int i = 0; i < 1000000; i++)
                arr.Add(i);

            //ArrayList 计时段
            TimeSpan ts1 = DateTime.Now - dt;

            //List 计时开始
            dt = DateTime.Now;

            //将100万个元素加入List
            for (int i = 0; i < 1000000; i++)
                lst.Add(i);

            //List 计时段
            TimeSpan ts2 = DateTime.Now - dt;


            Console.WriteLine(string.Format("ArrayList 耗时：{0} ms", ts1.Milliseconds));
            Console.WriteLine(string.Format("List<T> 耗时：{0} ms", ts2.Milliseconds));

            Console.ReadKey();
        }
    }
}

1.3

using System;

namespace DemoDelegate1
{
    /// <summary>
    /// 定义一个没有返回类型的委托
    /// </summary>
    delegate void myDelgage(string s);

    /// <summary>
    /// 定义一个有返回类型的委托
    /// </summary>
    delegate string myDelgageString(string s, bool man);

    class Program
    {
        /// <summary>
        /// 没有返回的方法
        /// </summary>
        static void Show1(string s)
        {
            Console.WriteLine(string.Format("  你好, {0}!", s));
        }
        static void Show2(string s)
        {
            Console.WriteLine(string.Format("  早上好, {0}!", s));
        }
        static void Show3(string s)
        {
            Console.WriteLine(string.Format("  晚上好, {0}!", s));
        }

        /// <summary>
        /// 返回字符串的方法
        /// </summary>
        static string AddTitle(string s, bool man)
        {
            if (man)
                return string.Format("  你好, {0} 先生", s);
            else
                return string.Format("  你好, {0} 女士", s);
        }

        static void Main(string[] args)
        {
            string name = "林晚荣";
            string name2 = "徐芷晴";

            //.NET 1.1 的委托实例化
            myDelgage del1 = new myDelgage(Show1);
            Console.WriteLine("  .NET 1.1 的委托调用");
            del1(name);
            Console.WriteLine("***********************************");

            //.NET 2.0 以上的委托实例化
            myDelgage del2 = Show1;
            Console.WriteLine("  .NET 2.0 以上的委托调用");
            del2(name);
            Console.WriteLine("***********************************");

            //多路委托绑定
            Console.WriteLine("  多路委托绑定调用");
            del2 += Show2;
            del2 += Show3;
            del2(name);
            Console.WriteLine("\n  合并掉Show1委托调用");
            del2 -= Show1;
            del2(name);
            Console.WriteLine("***********************************");

            //返回类型的委托
            myDelgageString del3 = AddTitle;

            Console.WriteLine("  返回类型的委托调用");
            Console.WriteLine(del3(name, true));
            Console.WriteLine(del3(name2, false));

            Console.ReadKey();
        }

        public event myDelgage myEvet;
    }
}
1.4 自定义事件及其事件数据类和利用代理跨线程的数据传递
Public event EventHandler myEvent;

namespace DemoDelegate2
{
    partial class EventDemo
    {
        /// <summary>
        /// 必需的设计器变量。
        /// </summary>
        private System.ComponentModel.IContainer components = null;

        /// <summary>
        /// 清理所有正在使用的资源。
        /// </summary>
        /// <param name="disposing">如果应释放托管资源，为 true；否则为 false。</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #region Windows 窗体设计器生成的代码

        /// <summary>
        /// 设计器支持所需的方法 - 不要
        /// 使用代码编辑器修改此方法的内容。
        /// </summary>
        private void InitializeComponent()
        {
            this.but = new System.Windows.Forms.Button();
            this.progressBar = new System.Windows.Forms.ProgressBar();
            this.SuspendLayout();
            //
            // but
            //
            this.but.Location = new System.Drawing.Point(172, 35);
            this.but.Name = "but";
            this.but.Size = new System.Drawing.Size(75, 23);
            this.but.TabIndex = 0;
            this.but.Text = "开始";
            this.but.UseVisualStyleBackColor = true;
            this.but.Click += new System.EventHandler(this.but_Click);
            //
            // progressBar
            //
            this.progressBar.Location = new System.Drawing.Point(12, 95);
            this.progressBar.Name = "progressBar";
            this.progressBar.Size = new System.Drawing.Size(235, 23);
            this.progressBar.TabIndex = 1;
            //
            // EventDemo
            //
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 12F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(259, 149);
            this.Controls.Add(this.progressBar);
            this.Controls.Add(this.but);
            this.Name = "EventDemo";
            this.Text = "自定义事件演示";
            this.ResumeLayout(false);

        }

        #endregion

        private System.Windows.Forms.Button but;
        private System.Windows.Forms.ProgressBar progressBar;
    }
}

namespace DemoDelegate2
{
    partial class EventDemo
    {
        /// <summary>
        /// 必需的设计器变量。
        /// </summary>
        private System.ComponentModel.IContainer components = null;

        /// <summary>
        /// 清理所有正在使用的资源。
        /// </summary>
        /// <param name="disposing">如果应释放托管资源，为 true；否则为 false。</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #region Windows 窗体设计器生成的代码

        /// <summary>
        /// 设计器支持所需的方法 - 不要
        /// 使用代码编辑器修改此方法的内容。
        /// </summary>
        private void InitializeComponent()
        {
            this.but = new System.Windows.Forms.Button();
            this.progressBar = new System.Windows.Forms.ProgressBar();
            this.SuspendLayout();
            //
            // but
            //
            this.but.Location = new System.Drawing.Point(172, 35);
            this.but.Name = "but";
            this.but.Size = new System.Drawing.Size(75, 23);
            this.but.TabIndex = 0;
            this.but.Text = "开始";
            this.but.UseVisualStyleBackColor = true;
            this.but.Click += new System.EventHandler(this.but_Click);
            //
            // progressBar
            //
            this.progressBar.Location = new System.Drawing.Point(12, 95);
            this.progressBar.Name = "progressBar";
            this.progressBar.Size = new System.Drawing.Size(235, 23);
            this.progressBar.TabIndex = 1;
            //
            // EventDemo
            //
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 12F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(259, 149);
            this.Controls.Add(this.progressBar);
            this.Controls.Add(this.but);
            this.Name = "EventDemo";
            this.Text = "自定义事件演示";
            this.ResumeLayout(false);

        }

        #endregion

        private System.Windows.Forms.Button but;
        private System.Windows.Forms.ProgressBar progressBar;
    }
}


using System;

namespace DemoDelegate2
{
    /// <summary>
    /// 自定义的事件数据类
    /// </summary>
    public class MyEnentArgs : EventArgs
    {
        /// <summary>
        /// 需要传递的数据
        /// </summary>
        public int Number { get; private set; }

        public MyEnentArgs(int n)
        {
            this.Number = n;
        }
    }

}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;

namespace DemoDelegate2
{
    static class Program
    {
        /// <summary>
        /// 应用程序的主入口点。
        /// </summary>
        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new EventDemo());
        }
    }
}


using System;
using System.Windows.Forms;
using System.Threading;

namespace DemoDelegate2
{
    public partial class EventDemo : Form
    {
        /// <summary>
        /// 定义事件
        /// </summary>
        public event EventHandler<MyEnentArgs> Half;

        /// <summary>
        /// 定义一个用于更新界面的委托
        /// </summary>
        /// <param name="?"></param>
        private delegate void UpdateCtlDelegate(int data, bool evt, bool over);

        public EventDemo()
        {
            InitializeComponent();

            //挂载事件处理函数
            this.Half += new EventHandler<MyEnentArgs>(EventDemo_Half);
        }

        /// <summary>
        /// 自定义事件处理函数
        /// </summary>
        void EventDemo_Half(object sender, MyEnentArgs e)
        {
            MessageBox.Show(string.Format("参数数据:{0}", e.Number), "事件成功被引发");
        }

        /// <summary>
        /// 开始按钮Click事件处理
        /// </summary>
        private void but_Click(object sender, EventArgs e)
        {
            this.but.Enabled = false;
            //启动工作线程
            Thread th = new Thread(new ThreadStart(progress));
            th.IsBackground = true;
            th.Start();
        }

        /// <summary>
        /// 界面更新及事件引发
        /// </summary>
        private void update(int data, bool evt, bool over)
        {
            //检测是否需要返回界面线程
            if (this.InvokeRequired)
            {
                //通过委托返回界面线程
                this.BeginInvoke(new UpdateCtlDelegate(update), new object[] { data, evt, over });
                return;
            }

            //循环结束修改Button显示
            if (over)
            {
                this.but.Enabled = true;
                return;
            }

            if (evt)
            {
                //引发事件
                this.Half(this, new MyEnentArgs(data));
            }
            else
            {
                //更新进度条
                this.progressBar.Value = data;
            }
        }

        /// <summary>
        /// 工作线程处理方法
        /// </summary>
        private void progress()
        {
            for (int i = 0; i < 100; i++)
            {
                this.update(i, false, false);

                if (i == 50)
                {
                    if (this.Half != null)
                        this.update(i, true, false);
                }

                //延时
                System.Threading.Thread.Sleep(10);
            }

            this.update(0, false, true);
        }
    }
}

5 迭代器与yield 关键字
yield 关键字在迭代器中，用于向枚举对象返回元素值或发出迭代结束信号

yield return <expression>
yield break

using System;

namespace DemoInitializer1
{
    class Girlfriend
    {
        public string Name { get; set; }
        public int Age { get; set; }
    }

    class Boy
    {
        public string Name { get; set; }
        public int Age { get; set; }
        public Girlfriend Girl{ get; set; }
    }

    class Program
    {
        static void Main(string[] args)
        {
            //用对象初始化器创建对象
            Girlfriend gf1 = new Girlfriend { Name = "秦仙儿",  };

            //等价于
            Girlfriend gf2 = new Girlfriend();
            gf2.Name = "萧玉若";
            gf2.Age = 21;

            //用嵌套的对象初始化器创建对象
            Boy boy1 = new Boy { Name = "林晚荣", Age = 24, Girl = new Girlfriend { Name = "肖青漩", Age = 20 } };

            //等价于
            Boy boy2 = new Boy();
            Girlfriend gf3 = new Girlfriend();

            gf3.Name = "董巧巧";
            gf3.Age = 18;
            boy2.Name = "林三";
            boy2.Age = 24;
            boy2.Girl = gf3;

            Console.WriteLine("gf1 初始化的类型：" + gf1.GetType().Name);
            Console.WriteLine("boy1 初始化的类型：" + boy1.GetType().Name);

            Console.ReadKey();
        }
    }
}


7 、隐式类型的局部变量 var
var 类型的确定由初始化语句的右侧的表达式推断出来的


using System;
using System.Collections.Generic;

namespace DemoVar
{
    class Program
    {
        static void Main(string[] args)
        {
            var str = "测试字符串";
            var i = 123456;
            var lst = new List<string>();
            var arr = new string[] { "大华军师", "金刀可汗", "圣坊仙子", "金陵才女" };

            Console.WriteLine(string.Format("变量 str 的数据类型：{0}", str.GetType().Name));
            Console.WriteLine(string.Format("变量 i 的数据类型：{0}", i.GetType().Name));
            Console.WriteLine(string.Format("变量 lst 的数据类型：{0}", lst.GetType().Name));
            Console.WriteLine(string.Format("变量 arr 的数据类型：{0}", arr.GetType().Name));

            Console.ReadKey();
        }
    }
}
变量 str 的数据类型：String
变量 i 的数据类型：Int32
变量 lst 的数据类型：List`1
变量 arr 的数据类型：String[]


8对象和集合初始化器

8.1 对象的初始化
using System;

namespace DemoInitializer1
{
    class Girlfriend
    {
        public string Name { get; set; }
        public int Age { get; set; }
    }

    class Boy
    {
        public string Name { get; set; }
        public int Age { get; set; }
        public Girlfriend Girl{ get; set; }
    }

    class Program
    {
        static void Main(string[] args)
        {
            //用对象初始化器创建对象
            Girlfriend gf1 = new Girlfriend { Name = "秦仙儿",  };

            //等价于
            Girlfriend gf2 = new Girlfriend();
            gf2.Name = "萧玉若";
            gf2.Age = 21;

            //用嵌套的对象初始化器创建对象
            Boy boy1 = new Boy { Name = "林晚荣", Age = 24, Girl = new Girlfriend { Name = "肖青漩", Age = 20 } };

            //等价于
            Boy boy2 = new Boy();
            Girlfriend gf3 = new Girlfriend();

            gf3.Name = "董巧巧";
            gf3.Age = 18;
            boy2.Name = "林三";
            boy2.Age = 24;
            boy2.Girl = gf3;

            Console.WriteLine("gf1 初始化的类型：" + gf1.GetType().Name);
            Console.WriteLine("boy1 初始化的类型：" + boy1.GetType().Name);

            Console.ReadKey();
        }
    }
}


8.2 集合初始化化

using System;
using System.Collections.Generic;

namespace DemoInitializer2
{
    /// <summary>
    /// 演示对象
    /// </summary>
    class Girlfriend
    {
        public string Name { get; set; }
        public int Age { get; set; }
    }

    /// <summary>
    /// 演示对象
    /// </summary>
    class Boy
    {
        public string Name { get; set; }
        public int Age { get; set; }

        /// <summary>
        /// 集合属性
        /// </summary>
        public List<Girlfriend> Girls { get; set;}
    }


    class Program
    {
        static void Main(string[] args)
        {
            //用集合初始化器创建集合
            List<string> gfs1 = new List<string> { "肖青漩", "董巧巧", "萧玉霜" };

            //等价于
            List<string> gfs2 = new List<string>();
            gfs2.Add("肖青漩");
            gfs2.Add("董巧巧");
            gfs2.Add("萧玉霜");

            //对象集合初始化器复合使用
            Boy boy = new Boy { Name = "林晚荣", Age = 24,
                                    Girls = new List<Girlfriend>
                                    {
                                        new Girlfriend { Name = "肖青漩", Age = 23 },
                                        new Girlfriend { Name = "董巧巧", Age = 18 },
                                        new Girlfriend { Name = "萧玉霜", Age = 16 }
                                    }
                               };


            Console.ReadKey();

        }
    }
}

2.28 匿名类型
使用new 运算符和对象初始值设定项来创建。


using System;
using System.Collections.Generic;
using System.Linq;

namespace DemoAnonymousType
{
    class Program
    {
        static void Main(string[] args)
        {
            ///创建匿名类型
            var anonymous1 = new { Name = "安碧如", Title = "苗族圣姑", Age = 36 };
            var anonymous2 = new { Name = "宁雨昔", Title = "圣坊仙子", Age = 37 };

            List<string> lst = new List<string> { "高丽公主", "大华军师", "霓裳公主" };

            Console.WriteLine(string.Format("anonymous1的类型：{0}", anonymous1.GetType().Name));
            Console.WriteLine(string.Format("{0} {1} {2}", anonymous1.Name, anonymous1.Title, anonymous1.Age));

            Console.WriteLine(string.Format("anonymous2的类型：{0}", anonymous2.GetType().Name));
            Console.WriteLine(string.Format("{0} {1} {2}", anonymous2.Name, anonymous2.Title, anonymous2.Age));

            Console.WriteLine("\n*******************************************\n");

            //LINQ select 子句中创建匿名类型
            var query = from n in lst
                        where n.IndexOf("公主") > -1
                        select new { Name = "查询元素", Title = n };

            foreach (var item in query)
            {
                Console.WriteLine(string.Format("元素的类型：{0}", item.GetType().Name));
                Console.WriteLine(string.Format("{0} {1}", item.Name, item.Title));
            }

            Console.ReadKey();
        }
    }
}

10 扩展方法
using System;

namespace DemoExtensionMethods
{
    public class Program
    {
        static void Main(string[] args)
        {
            string subb = "[a]http://www.baidu.com[/a]";

            Console.WriteLine(subb.UbbToHtmlLink());

            Console.WriteLine("\n");

            int i = 5;

            Console.WriteLine(string.Format("检测 i 是否为偶数：{0}",i.IsEven()));

            Console.WriteLine("\n");

            Program p = new Program();

            p.ExtensionShow();

            Console.ReadKey();
        }

    }
}

12创建匿名方法

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace DemoAnony
{
    class Program
    {
        delegate void DemoDelegate();
        static void Main(string[] args)
        {
            DemoDelegate dele = delegate { Console.WriteLine("From the anonymousMethod"); };
            dele();
            Console.ReadKey();

        }
    }
}
13、创建Lambda表达式

using System;
using System.Linq.Expressions;

namespace DemoLambda1
{
    class Program
    {
        delegate string MyDelegate(string title, string name);

        //delegate T MyDelegate2<T>(T a, T b);

        static void Main(string[] args)
        {
            //定义Lambda表达式
            MyDelegate dele = (title, name) => string.Format("{0} {1}", title, name);

            Console.WriteLine("调用Lambda表达式\n");
            //调用Lambda表达式
            Console.WriteLine(dele("出云公主", "肖青漩"));
            Console.WriteLine(dele("乖巧人儿", "董巧巧"));
            Console.WriteLine(dele("萧家二小姐", "萧玉霜"));

            Console.WriteLine("\n*******************\n");

            string tmp = "我是Lambda语句外的变量";

            //定义Lambda语句
            MyDelegate dele2 = (title, name) =>
            {
                Console.WriteLine("从Lambda语句体中输出");
                Console.WriteLine(string.Format("输出外部变量tmp：{0}", tmp));
                string s;
                s = string.Format("{0} {1} 小姐", title, name);

                return s;
            };

            Console.WriteLine("调用Lambda语句\n");
            //调用Lambda表达式
            Console.WriteLine(dele2("霓裳公主", "秦仙儿"));


            Console.ReadKey();
        }
    }
}

14 Lambda 表达式树
using System;
using System.Linq.Expressions;

namespace DemoLambda2
{
    class Program
    {
        static void Main(string[] args)
        {
            //定义Lambd表达式目录树
            Expression<Func<int, bool>> tree = n => n > 168;

            //分解表达式
            BinaryExpression body = (BinaryExpression)tree.Body;
            ParameterExpression left = (ParameterExpression)body.Left;
            ConstantExpression right = (ConstantExpression)body.Right;

            //分解结果
            Console.WriteLine("分解结果: {0} {1} {2}\n",
                              left.Name, body.NodeType, right.Value);

            //编译目录树
            Func<int, bool> t = tree.Compile();


            //执行目录树
            Console.WriteLine(string.Format("1000 是否大于 168 :{0}", t(1000)));


            Console.ReadKey();
        }
    }
}

15  C#高亮编辑及编译运行器

using System;
using System.Windows.Forms;

namespace DemoCSharpEditor
{
    public partial class Editor : Form
    {
        /// <summary>
        /// 控制器
        /// </summary>
        private EditorController ec;

        public Editor()
        {
            InitializeComponent();
            //初始化控制器
            ec = new EditorController(this.richt,this.txtlog);
        }

        private void 运行ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            ec.Compile();
        }

        private void 退出ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Close();
        }

        private void Editor_Load(object sender, EventArgs e)
        {

        }
    }
}
namespace DemoCSharpEditor
{
    partial class Editor
    {
        /// <summary>
        /// 必需的设计器变量。
        /// </summary>
        private System.ComponentModel.IContainer components = null;

        /// <summary>
        /// 清理所有正在使用的资源。
        /// </summary>
        /// <param name="disposing">如果应释放托管资源，为 true；否则为 false。</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #region Windows 窗体设计器生成的代码

        /// <summary>
        /// 设计器支持所需的方法 - 不要
        /// 使用代码编辑器修改此方法的内容。
        /// </summary>
        private void InitializeComponent()
        {
            this.mainmenu = new System.Windows.Forms.MenuStrip();
            this.文件FToolStripMenuItem = new System.Windows.Forms.ToolStripMenuItem();
            this.打开OToolStripMenuItem = new System.Windows.Forms.ToolStripMenuItem();
            this.保存SToolStripMenuItem = new System.Windows.Forms.ToolStripMenuItem();
            this.toolStripMenuItem1 = new System.Windows.Forms.ToolStripSeparator();
            this.退出ToolStripMenuItem = new System.Windows.Forms.ToolStripMenuItem();
            this.运行RToolStripMenuItem = new System.Windows.Forms.ToolStripMenuItem();
            this.运行ToolStripMenuItem = new System.Windows.Forms.ToolStripMenuItem();
            this.richt = new System.Windows.Forms.RichTextBox();
            this.txtlog = new System.Windows.Forms.TextBox();
            this.mainmenu.SuspendLayout();
            this.SuspendLayout();
            //
            // mainmenu
            //
            this.mainmenu.Items.AddRange(new System.Windows.Forms.ToolStripItem[] {
            this.文件FToolStripMenuItem,
            this.运行RToolStripMenuItem});
            this.mainmenu.Location = new System.Drawing.Point(0, 0);
            this.mainmenu.Name = "mainmenu";
            this.mainmenu.Padding = new System.Windows.Forms.Padding(8, 2, 0, 2);
            this.mainmenu.Size = new System.Drawing.Size(408, 28);
            this.mainmenu.TabIndex = 0;
            this.mainmenu.Text = "menuStrip1";
            //
            // 文件FToolStripMenuItem
            //
            this.文件FToolStripMenuItem.DropDownItems.AddRange(new System.Windows.Forms.ToolStripItem[] {
            this.打开OToolStripMenuItem,
            this.保存SToolStripMenuItem,
            this.toolStripMenuItem1,
            this.退出ToolStripMenuItem});
            this.文件FToolStripMenuItem.Name = "文件FToolStripMenuItem";
            this.文件FToolStripMenuItem.ShortcutKeys = ((System.Windows.Forms.Keys)((System.Windows.Forms.Keys.Control | System.Windows.Forms.Keys.S)));
            this.文件FToolStripMenuItem.Size = new System.Drawing.Size(69, 24);
            this.文件FToolStripMenuItem.Text = "文件(&F)";
            //
            // 打开OToolStripMenuItem
            //
            this.打开OToolStripMenuItem.Name = "打开OToolStripMenuItem";
            this.打开OToolStripMenuItem.ShortcutKeys = ((System.Windows.Forms.Keys)((System.Windows.Forms.Keys.Control | System.Windows.Forms.Keys.O)));
            this.打开OToolStripMenuItem.Size = new System.Drawing.Size(188, 24);
            this.打开OToolStripMenuItem.Text = "打开(&O)";
            //
            // 保存SToolStripMenuItem
            //
            this.保存SToolStripMenuItem.Name = "保存SToolStripMenuItem";
            this.保存SToolStripMenuItem.ShortcutKeys = ((System.Windows.Forms.Keys)((System.Windows.Forms.Keys.Control | System.Windows.Forms.Keys.S)));
            this.保存SToolStripMenuItem.Size = new System.Drawing.Size(188, 24);
            this.保存SToolStripMenuItem.Text = "保存(&S)";
            //
            // toolStripMenuItem1
            //
            this.toolStripMenuItem1.Name = "toolStripMenuItem1";
            this.toolStripMenuItem1.Size = new System.Drawing.Size(185, 6);
            //
            // 退出ToolStripMenuItem
            //
            this.退出ToolStripMenuItem.Name = "退出ToolStripMenuItem";
            this.退出ToolStripMenuItem.Size = new System.Drawing.Size(188, 24);
            this.退出ToolStripMenuItem.Text = "退出(&Q)";
            this.退出ToolStripMenuItem.Click += new System.EventHandler(this.退出ToolStripMenuItem_Click);
            //
            // 运行RToolStripMenuItem
            //
            this.运行RToolStripMenuItem.DropDownItems.AddRange(new System.Windows.Forms.ToolStripItem[] {
            this.运行ToolStripMenuItem});
            this.运行RToolStripMenuItem.Name = "运行RToolStripMenuItem";
            this.运行RToolStripMenuItem.Size = new System.Drawing.Size(71, 24);
            this.运行RToolStripMenuItem.Text = "运行(&R)";
            //
            // 运行ToolStripMenuItem
            //
            this.运行ToolStripMenuItem.Name = "运行ToolStripMenuItem";
            this.运行ToolStripMenuItem.ShortcutKeys = ((System.Windows.Forms.Keys)((System.Windows.Forms.Keys.Control | System.Windows.Forms.Keys.R)));
            this.运行ToolStripMenuItem.Size = new System.Drawing.Size(164, 24);
            this.运行ToolStripMenuItem.Text = "运行";
            this.运行ToolStripMenuItem.Click += new System.EventHandler(this.运行ToolStripMenuItem_Click);
            //
            // richt
            //
            this.richt.AcceptsTab = true;
            this.richt.Dock = System.Windows.Forms.DockStyle.Fill;
            this.richt.Font = new System.Drawing.Font("新宋体", 9.75F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(134)));
            this.richt.Location = new System.Drawing.Point(0, 28);
            this.richt.Margin = new System.Windows.Forms.Padding(4, 4, 4, 4);
            this.richt.Name = "richt";
            this.richt.Size = new System.Drawing.Size(408, 183);
            this.richt.TabIndex = 1;
            this.richt.Text = "";
            //
            // txtlog
            //
            this.txtlog.Dock = System.Windows.Forms.DockStyle.Bottom;
            this.txtlog.Location = new System.Drawing.Point(0, 211);
            this.txtlog.Margin = new System.Windows.Forms.Padding(4, 4, 4, 4);
            this.txtlog.Multiline = true;
            this.txtlog.Name = "txtlog";
            this.txtlog.ScrollBars = System.Windows.Forms.ScrollBars.Vertical;
            this.txtlog.Size = new System.Drawing.Size(408, 109);
            this.txtlog.TabIndex = 2;
            this.txtlog.WordWrap = false;
            //
            // Editor
            //
            this.AutoScaleDimensions = new System.Drawing.SizeF(8F, 15F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(408, 320);
            this.Controls.Add(this.richt);
            this.Controls.Add(this.txtlog);
            this.Controls.Add(this.mainmenu);
            this.KeyPreview = true;
            this.MainMenuStrip = this.mainmenu;
            this.Margin = new System.Windows.Forms.Padding(4, 4, 4, 4);
            this.Name = "Editor";
            this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen;
            this.Text = "C Sharp 代码编辑器";
            this.WindowState = System.Windows.Forms.FormWindowState.Maximized;
            this.Load += new System.EventHandler(this.Editor_Load);
            this.mainmenu.ResumeLayout(false);
            this.mainmenu.PerformLayout();
            this.ResumeLayout(false);
            this.PerformLayout();

        }

        #endregion

        private System.Windows.Forms.MenuStrip mainmenu;
        private System.Windows.Forms.ToolStripMenuItem 文件FToolStripMenuItem;
        private System.Windows.Forms.ToolStripMenuItem 打开OToolStripMenuItem;
        private System.Windows.Forms.ToolStripMenuItem 保存SToolStripMenuItem;
        private System.Windows.Forms.ToolStripSeparator toolStripMenuItem1;
        private System.Windows.Forms.ToolStripMenuItem 退出ToolStripMenuItem;
        private System.Windows.Forms.ToolStripMenuItem 运行RToolStripMenuItem;
        private System.Windows.Forms.ToolStripMenuItem 运行ToolStripMenuItem;
        private System.Windows.Forms.RichTextBox richt;
        private System.Windows.Forms.TextBox txtlog;
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;
using System.IO;
using System.Drawing;
using System.CodeDom.Compiler;
using Microsoft.CSharp;
using System.Reflection;

namespace DemoCSharpEditor
{
    /// <summary>
    /// 控制器
    /// </summary>
    public class EditorController
    {
        /// <summary>
        /// 高亮字颜色
        /// </summary>
        public Color LightColor { get; set; }

        /// <summary>
        /// 文本色
        /// </summary>
        public Color TextColor { get; set; }

        /// <summary>
        /// RichTextBox 控件引用
        /// </summary>
        private RichTextBox rich;

        private TextBox loginfo;

        /// <summary>
        /// 关键字列表
        /// </summary>
        private List<string> keywords = new List<string>();

        public EditorController(RichTextBox r, TextBox l)
        {
            if (r == null || l == null)
                throw new Exception("控制器，初始化失败。");

            this.loginfo = l;
            this.rich = r;
            this.rich.KeyUp += new KeyEventHandler(rich_KeyUp);
            this.LoadKeyWord();

            this.LightColor = Color.Blue;
            this.TextColor = this.rich.ForeColor;
        }

        void rich_KeyUp(object sender, KeyEventArgs e)
        {
            if (e.KeyValue < 229)
                this.LightCurrentKeyWord();
        }

        /// <summary>
        /// 从文本文件装载关键字列表
        /// </summary>
        private void LoadKeyWord()
        {
            string sf = "cs.txt";

            if (File.Exists(sf))
            {
                keywords.Clear();
                using (StreamReader sr = new StreamReader(sf))
                {
                    string sl = sr.ReadLine();
                    do
                    {
                        if (sl != null)
                            keywords.Add(sl);

                        sl = sr.ReadLine();
                    } while (sl != null);
                }
            }
        }

        /// <summary>
        /// 高亮关键字
        /// </summary>
        private void LightCurrentKeyWord()
        {
            CurrentWord last = this.rich.Text.CursorWord(this.rich.SelectionStart);

            if (last != null)
            {
                var query = from w in this.keywords
                            where w == last.Word
                            select w;

                int oldindex = this.rich.SelectionStart;
                int oldleng = this.rich.SelectionLength;
                this.rich.SelectionStart = last.StartIndex;
                this.rich.SelectionLength = last.Length;

                if (query.Count<string>() > 0)
                {
                    this.rich.SelectionColor = this.LightColor;
                }
                else
                {
                    this.rich.SelectionColor = this.TextColor;
                }

                this.rich.SelectionLength = oldleng;
                this.rich.SelectionStart = oldindex;
                this.rich.SelectionColor = this.TextColor;
            }
        }

        /// <summary>
        /// 格式化代码
        /// </summary>
        private string MakeCode()
        {
            string code = @"
                    using System;
                    using System.Collections.Generic;
                    using System.ComponentModel;
                    using System.Data;
                    using System.Drawing;
                    using System.Text;
                    using System.Windows.Forms;
                    namespace DemoTest
                    {
                        public class Test
                        {
                            public void TestMethod()
                            {"
                                + this.rich.Text + @"
                            }
                        }
                    }";
            return code;
        }

        /// <summary>
        /// 编译并运行代码
        /// </summary>
        public void Compile()
        {
            this.loginfo.Text = "信息：准备编译。\n";
            using (CSharpCodeProvider provider = new CSharpCodeProvider())
            {
                string[] refs = { "System.dll", "System.Data.dll", "System.Deployment.dll", "System.Drawing.dll", "System.Windows.Forms.dll", "System.Xml.dll" };

                CompilerParameters opt = new CompilerParameters();
                opt.ReferencedAssemblies.AddRange(refs);

                CompilerResults res = provider.CompileAssemblyFromSource(opt, this.MakeCode());

                if (res.Errors.Count > 0)
                {
                    foreach (CompilerError e in res.Errors)
                        this.loginfo.AppendText(string.Format("编译错误：{0}\n", e.ErrorText));
                    return;
                }

                this.loginfo.AppendText("信息：编译成功，准备运行。\n");
                try
                {
                    Assembly assembly = res.CompiledAssembly;
                    Type type = assembly.GetType("DemoTest.Test");
                    object obj = Activator.CreateInstance(type);
                    this.loginfo.AppendText("信息：运行。\n");
                    type.GetMethod("TestMethod").Invoke(obj, null);
                }
                catch (Exception e)
                {
                    this.loginfo.AppendText(string.Format("运行错误：{0} \n  {1} \n", e.Message, e.StackTrace));
                }

                this.loginfo.AppendText("完毕。\n");
            }
        }


    }
}

using System;
using System.Linq;

namespace DemoCSharpEditor
{
    /// <summary>
    /// String 扩展
    /// </summary>
    public static class EditorExtension
    {
        /// <summary>
        /// 单词分隔字符数组
        /// </summary>
        public static char[] SplitChar = { ' ', ',', '.', ';', '\n', '{', '}', '\r', Convert.ToChar(9),'(',')','[',']' };

        /// <summary>
        /// 检测字符是否分割字符
        /// </summary>
        public static bool IsSplit(this Char chr)
        {

            var query = SplitChar.Where(c => c == chr);

            if (query.Count<char>() > 0)
                return true;
            else
                return false;
        }


        /// <summary>
        /// 检测字符串最后一个字符是否是分割字符
        /// </summary>
        public static bool LastCharIsSplit(this string str, int cursorinde)
        {
            if (cursorinde < 1)
                return false;

            var sec = from c in SplitChar
                      where c == str[cursorinde - 1]
                      select c;

            if (sec.Count<char>() > 0)
                return true;
            else
                return false;
        }

        /// <summary>
        /// 光标所在的单词
        /// </summary>
        public static CurrentWord CursorWord(this string str, int cursorindex)
        {
            if (string.IsNullOrEmpty(str))
                return null;

            if (cursorindex < 2)
                return null;

            int i = str.LastIndexOfAny(SplitChar, cursorindex - 2);
            int ed = cursorindex - 2;

            if (ed < 1)
                ed = str.Length;

            if (i < 0)
                i = 0;
            else
                i = i + 1;

            if (ed < str.Length)
            {
                //光标不在字符串尾部,向后搜索
                ed = str.IndexOfAny(SplitChar, ed);
            }

            if (ed < 0)
                return null;

            char lastc = str[ed - 1];
            if (lastc.IsSplit())
                ed = ed - 1;

            ed = ed - i;

            if (ed < 1)
                return null;

            return new CurrentWord
            {
                StartIndex = i,
                Length = ed,
                Word = str.Substring(i, ed)
            };
        }
    }
}
using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;

namespace DemoCSharpEditor
{
    static class Program
    {
        /// <summary>
        /// 应用程序的主入口点。
        /// </summary>
        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new Editor());
        }
    }
}

3.1  LINQ
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace DemoLinq1
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] values = { "巧巧", "李四", "林三哥", "王五" };

            var value = from v in values where v.Length > 2 select v;

            foreach (var n in value)
                Console.WriteLine(n);

            Console.ReadKey();
        }
    }
}

3.2  from
using System.Collections.Generic;

namespace DemoLinq
{
    /// <summary>
    /// 客户信息
    /// </summary>
    public class GuestInfo
    {
        /// <summary>
        /// 姓名
        /// </summary>
        public string Name { set; get; }
        /// <summary>
        /// 年龄
        /// </summary>
        public int Age { set; get; }

        /// <summary>
        /// 电话
        /// </summary>
        public string Tel { set; get; }

        /// <summary>
        /// 电话表
        /// </summary>
        public List<string> TelTable { set; get; }

    }
}

using System;
using System.Linq;
using System.Collections;
using DemoLinq;

namespace DemoLinq2
{
    class Program
    {
        static void Main(string[] args)
        {
            //初始化ArrayList
            ArrayList gList = new ArrayList();
            gList.Add(
                new GuestInfo { Name = "林晚荣", Age = 21, Tel = "888888**" }
                );

            gList.Add(
                   new GuestInfo { Name = "宁雨昔", Age = 36, Tel = "568923**" }
                   );

            gList.Add(
                   new GuestInfo { Name = "洛凝", Age = 19, Tel = "985690**" }
                   );

            //查询 年龄大于 19 的客户
            var query = from GuestInfo guest in gList
                        where guest.Age > 19
                        select guest;

            //输出
            foreach (GuestInfo g in query)
                Console.WriteLine(string.Format("{0} 年龄:{1} 电话:{2}", g.Name, g.Age, g.Tel));

            Console.ReadKey();

        }
    }
}

3.2/2复合from

using System;
using System.Collections.Generic;
using System.Linq;
using DemoLinq;

namespace DemoFrom1
{
    class Program
    {
        static void Main(string[] args)
        {
            //初始化集合
            List<GuestInfo> gList = new List<GuestInfo>()
            {
                new GuestInfo {
                    Name = "林晚荣",
                    Age = 21,
                    TelTable = new List<string>(){
                        "026*-888888**",
                        "13802588***"}
                },
                new GuestInfo {
                    Name = "宁雨昔",
                    Age = 36,
                    TelTable = new List<string>(){
                        "098*-568923**",
                        "132679856**"}
                },
                new GuestInfo {
                    Name = "洛凝",
                    Age = 19,
                    TelTable = new List<string>(){
                        "033*-985690**",
                        "153129057**"}
                },
            };

            //查找 电话号码 ：132679856** 属于哪个客户
            var query = from guest in gList
                        from tel in guest.TelTable
                        where tel.IndexOf("132679856**") > -1
                        select guest;

            //输出
            foreach (var g in query)
            {
                Console.WriteLine(string.Format("{0} 年龄:{1}", g.Name, g.Age));
                foreach (var t in g.TelTable)
                    Console.WriteLine(string.Format("       电话：{0}", t));
            }

            Console.ReadKey();
        }
    }
}

3.2.3 多个from 子句
using System;
using System.Collections.Generic;
using System.Linq;
using DemoLinq;

namespace DemoFrom2
{
    class Program
    {
        static void Main(string[] args)
        {
            //初始化集合
            List<GuestInfo> gList = new List<GuestInfo>()
            {
                new GuestInfo
                {
                    Name = "林晚荣",
                    Age = 21,
                    Tel = "026*-888888**" },
                new GuestInfo
                {
                    Name = "肖青漩",
                    Age = 21,
                    Tel = "017*-876543**"
                },
                new GuestInfo
                {
                    Name = "董巧巧",
                    Age = 19,
                    Tel = "029*-981256**"
                },
            };

            List<GuestInfo> gList2 = new List<GuestInfo>()
            {
                new GuestInfo
                {
                    Name = "萧玉霜",
                    Age = 17,
                    Tel = "137052668**"
                },
                new GuestInfo
                {
                    Name = "秦仙儿",
                    Age = 20,
                    Tel = "151983676**"
                },
                new GuestInfo
                {
                    Name = "萧玉若",
                    Age = 21,
                    Tel = "152987235**"
                },
            };

            //guest 表查找Age大于20，
            //guest2 查找Age大于17，
            //结果交叉链接
            var query = from guest in gList
                        where guest.Age > 20
                        from guest2 in gList2
                        where guest2.Age > 17
                        select new { guest, guest2 };

            //输出

            foreach (var g in query)
                Console.WriteLine(string.Format("{0} {1}", g.guest.Name, g.guest2.Name));

            Console.ReadKey();
        }
    }
}

3.3 where 子句
using System;
using System.Collections.Generic;
using System.Linq;
using DemoLinq;

namespace DemoWhere1
{
    class Program
    {
        static void Main(string[] args)
        {
            //初始化集合
            List<GuestInfo> gList = new List<GuestInfo>()
            {
                new GuestInfo
                {
                    Name = "林晚荣",
                    Age = 21,
                    Tel = "026*-888888**" },
                new GuestInfo
                {
                    Name = "肖青漩",
                    Age = 21,
                    Tel = "017*-876543**"
                },
                new GuestInfo
                {
                    Name = "董巧巧",
                    Age = 19,
                    Tel = "029*-981256**"
                },
            };



            ///名字是2个字或者姓"肖"
            ///并且 年龄大于等于19的客户
            var query = from guest in gList
                        where (guest.Name.Length == 2 ||
                                guest.Name.Substring(0, 1) == "肖") &&
                                guest.Age >= 19

                        select guest;


            foreach (var g in query)
                Console.WriteLine(string.Format("{0} 年龄:{1} 电话:{2}", g.Name, g.Age, g.Tel));

            Console.ReadKey();
        }
    }
}

3.3.2 在where 子句中使用自定义函数
using System;
using System.Collections.Generic;
using System.Linq;
using DemoLinq;

namespace DemoWhere2
{
    class Program
    {
        static void Main(string[] args)
        {
            //初始化集合
            List<GuestInfo> gList = new List<GuestInfo>()
            {
                new GuestInfo
                {
                    Name = "林晚荣",
                    Age = 21,
                    Tel = "026*-888888**" },
                new GuestInfo
                {
                    Name = "肖青漩",
                    Age = 21,
                    Tel = "017*-876543**"
                },
                new GuestInfo
                {
                    Name = "董巧巧",
                    Age = 19,
                    Tel = "029*-981256**"
                },
            };

            //查找名字是3个字并且第一个字是“董”的信息
            var query = from guest in gList
                        where guest.Name.Length == 3 &&
                                Check(guest.Name)

                        select guest;


            foreach (var g in query)
                Console.WriteLine(string.Format("{0} 年龄:{1} 电话:{2}", g.Name, g.Age, g.Tel));

            Console.ReadKey();

        }

        /// <summary>
        /// 自定义函数
        /// 检测是否姓“董”
        /// </summary>
        static bool Check(string name)
        {
            if (name.Substring(0, 1) == "董")
                return true;

            return false;
        }
    }
}

3.3.3 动态谓词的筛选

using System;
using System.Collections.Generic;
using System.Linq;
using DemoLinq;

namespace DemoWhere3
{
    class Program
    {
        static void Main(string[] args)
        {
            //初始化集合
            List<GuestInfo> gList = new List<GuestInfo>()
            {
                new GuestInfo
                {
                    Name = "林晚荣",
                    Age = 21,
                    Tel = "026*-888888**" },
                new GuestInfo
                {
                    Name = "肖青漩",
                    Age = 21,
                    Tel = "017*-876543**"
                },
                new GuestInfo
                {
                    Name = "董巧巧",
                    Age = 19,
                    Tel = "029*-981256**"
                },
            };

            //定义动态谓词数组
            string[] names = { "徐长今", "萧玉若", "肖青漩", "月牙儿" };

            //查找包含在动态谓词数组中的名字
            var query = from guest in gList
                        where names.Contains(guest.Name)
                        select guest;

            foreach (var g in query)
                Console.WriteLine(string.Format("{0} 年龄:{1} 电话:{2}", g.Name, g.Age, g.Tel));

            Console.ReadKey();

        }
    }
}

3.4 select 子句

using System;
using System.Collections.Generic;
using System.Linq;
using DemoLinq;

namespace DemoSelect1
{
    class Program
    {
        static void Main(string[] args)
        {
            //初始化集合
            List<GuestInfo> gList = new List<GuestInfo>()
            {
                new GuestInfo
                {
                    Name = "宁雨昔",
                    Age = 36,
                    Tel = "098*-568923**" },
                new GuestInfo
                {
                    Name = "肖青漩",
                    Age = 21,
                    Tel = "017*-876543**"
                },
                new GuestInfo
                {
                    Name = "董巧巧",
                    Age = 19,
                    Tel = "029*-981256**"
                },
            };


            //筛选年龄小于30的客户信息并投影成MyGuestInfo类型
            var query = from guest in gList
                        where guest.Age < 30
                        select new MyGuestInfo { Name = guest.Name, Tel = guest.Tel };

            foreach (var g in query)
                Console.WriteLine(string.Format("{0}  电话:{1} 类型：{2}", g.Name, g.Tel, g.ToString()));

            Console.ReadKey();
        }
    }
}


3.5  group
using System;
using System.Collections.Generic;
using System.Linq;
using DemoLinq;

namespace DemoGurop1
{
    class Program
    {
        static void Main(string[] args)
        {
            //初始化集合
            List<GuestInfo> gList = new List<GuestInfo>()
            {
                new GuestInfo
                {
                    Name = "萧玉霜",
                    Age = 17,
                    Tel = "053*-985690**" },
                new GuestInfo
                {
                    Name = "萧玉若",
                    Age = 21,
                    Tel = "035*-120967**"
                },
                new GuestInfo
                {
                    Name = "徐长今",
                    Age = 18,
                    Tel = "039*-967512**"
                },
                new GuestInfo
                {
                    Name = "徐芷晴",
                    Age = 24,
                    Tel = "089*-569832**"
                }
            };


            ////按照名字的第一个字进行分组
            //var query = from guest in gList
            //            group guest by guest.Name.Substring(0, 1);

            ////遍历分组数据
            //foreach (IGrouping<string, GuestInfo> guestGroup in query)
            //{
            //    //输出当前分组的键值
            //    Console.WriteLine(string.Format("分组键：{0} \n", guestGroup.Key));

            //    //遍历组内元素
            //    foreach (var g in guestGroup)
            //        Console.WriteLine(string.Format("{0}  电话:{1}", g.Name, g.Tel));
            //    Console.WriteLine("\n**********************************\n");
            //}



    //按照年龄是否大于20分组
    var query = from guest in gList
                group guest by guest.Age > 20;

    //遍历分组数据
    foreach (var guestGroup in query)
    {
        //输出当前分组的键值
        Console.WriteLine(string.Format("年龄是否大于 20 分组键：{0} \n", guestGroup.Key));

        //遍历组内元素
        foreach (var g in guestGroup)
            Console.WriteLine(string.Format("{0}  电话:{1}", g.Name, g.Tel));
        Console.WriteLine("\n**********************************\n");
    }

            Console.ReadKey();
        }
    }
}

3.6  into
using System;
using System.Collections.Generic;
using System.Linq;
using DemoLinq;

namespace DemoInto
{
    class Program
    {
        static void Main(string[] args)
        {
            //初始化集合
            List<GuestInfo> gList = new List<GuestInfo>()
            {
                new GuestInfo
                {
                    Name = "萧玉霜",
                    Age = 17,
                    Tel = "053*-985690**" },
                new GuestInfo
                {
                    Name = "萧玉若",
                    Age = 21,
                    Tel = "035*-120967**"
                },
                new GuestInfo
                {
                    Name = "徐长今",
                    Age = 18,
                    Tel = "039*-967512**"
                },
                new GuestInfo
                {
                    Name = "徐芷晴",
                    Age = 24,
                    Tel = "089*-569832**"
                }
            };

            //按照名字的第一个字进行分组并用分组key进行排序
            Console.WriteLine("into用于group子句的分组时刻");
            var query = from guest in gList
                        group guest by guest.Name.Substring(0, 1) into grguest
                        orderby grguest.Key descending
                        select grguest;

            //遍历分组数据
            foreach (var guestGroup in query)
            {
                //输出当前分组的键值
                Console.WriteLine(string.Format("分组键：{0} \n", guestGroup.Key));

                //遍历组内元素
                foreach (var g in guestGroup)
                    Console.WriteLine(string.Format("{0}  电话:{1}", g.Name, g.Tel));
                Console.WriteLine("\n**********************************\n");
            }

            Console.WriteLine("\ninto用于select子句的投影时刻");

            //select 子句中 的 info 子句使用
            var query2 = from guest in gList
                         select new{NewName = guest.Name, NewAge = guest.Age} into newguest
                         orderby newguest.NewAge
                         select newguest;

            //遍历分组数据
            foreach (var g in query2)
            {
                Console.WriteLine(string.Format("{0} 年龄：{1}", g.NewName,g.NewAge));
            }

            Console.ReadKey();
        }
    }
}

3.7 排序子句

using System;
using System.Collections.Generic;
using System.Linq;
using DemoLinq;

namespace DemoSort1
{
    class Program
    {
        static void Main(string[] args)
        {
            //初始化集合
            List<GuestInfo> gList = new List<GuestInfo>()
            {
                new GuestInfo
                {
                    Name = "林晚荣",
                    Age = 21,
                    Tel = "026*-888888**" },
                new GuestInfo
                {
                    Name = "宁雨昔",
                    Age = 36,
                    Tel = "098*-568923**"
                },
                new GuestInfo
                {
                    Name = "董巧巧",
                    Age = 19,
                    Tel = "029*-981256**"
                },
            };

            Console.WriteLine("按照年龄升序进行排序");
            ///按照年龄升序进行排序
            var query = from guest in gList
                        orderby guest.Age
                        select guest;

            foreach (var g in query)
                Console.WriteLine(string.Format("{0} 年龄:{1} 电话:{2}", g.Name, g.Age, g.Tel));


            Console.WriteLine("\n按照年龄降序进行排序");

            ///按照年龄降序进行排序
            query = from guest in gList
                    orderby guest.Age descending
                    select guest;

            foreach (var g in query)
                Console.WriteLine(string.Format("{0} 年龄:{1} 电话:{2}", g.Name, g.Age, g.Tel));

            Console.ReadKey();

        }
    }
}


3.7.2  ThenBy  和ThenByDescending

using System;
using System.Collections.Generic;
using System.Linq;
using DemoLinq;

namespace DemoSort2
{
    class Program
    {
        static void Main(string[] args)
        {
            //初始化集合
            List<GuestInfo> gList = new List<GuestInfo>()
            {
                new GuestInfo
                {
                    Name = "月牙儿",
                    Age = 18,
                    Tel = "067*-781256**"
                },
                new GuestInfo
                {
                    Name = "徐长今",
                    Age = 18,
                    Tel = "039*-967512**"
                },
                new GuestInfo
                {
                    Name = "依莲",
                    Age = 18,
                    Tel = "098*-231238**"
                },
                new GuestInfo
                {
                    Name = "董巧巧",
                    Age = 19,
                    Tel = "029*-981256**"
                },
            };

            Console.WriteLine("按照年龄进行排序、按照名字字数进行次要排序");
            ///按照年龄进行排序、按照名字字数进行次要排序
            var query = from guest in gList
                        orderby guest.Age,guest.Name.Length
                        select guest;

            foreach (var g in query)
                Console.WriteLine(string.Format("{0} 年龄:{1} 电话:{2}", g.Name, g.Age, g.Tel));

            Console.WriteLine("\n按照年龄进行排序、按照名字字数进行降序次要排序");

            ///按照年龄进行排序、按照名字字数进行降序次要排序
            query = from guest in gList
                    orderby guest.Age, guest.Name.Length descending
                    select guest;

            foreach (var g in query)
                Console.WriteLine(string.Format("{0} 年龄:{1} 电话:{2}", g.Name, g.Age, g.Tel));


            Console.WriteLine("\n按照年龄进行排序、名字字数、电话排序");

            ///按照年龄进行排序、按照名字字数进行次要排序、按照电话进行第三条件排序
            query = from guest in gList
                    orderby guest.Age, guest.Name.Length, guest.Tel
                    select guest;

            foreach (var g in query)
                Console.WriteLine(string.Format("{0} 年龄:{1} 电话:{2}", g.Name, g.Age, g.Tel));



            Console.ReadKey();
        }
    }
}

3.8   let 子句
using System;
using System.Collections.Generic;
using System.Linq;
using DemoLinq;

namespace DemoLet
{
    class Program
    {
        static void Main(string[] args)
        {
            //初始化集合
            List<GuestInfo> gList = new List<GuestInfo>()
            {
                new GuestInfo
                {
                    Name = "林晚荣",
                    Age = 21,
                    Tel = "026*-888888**" },
                new GuestInfo
                {
                    Name = "肖青漩",
                    Age = 21,
                    Tel = "017*-876543**"
                },
                new GuestInfo
                {
                    Name = "董巧巧",
                    Age = 19,
                    Tel = "029*-981256**"
                },
            };


            ///姓"肖"或姓 "董"的客户
            var query = from guest in gList
                        let g = guest.Name.Substring(0,1)
                        where g == "肖" || g == "董"
                        select guest;

            foreach (var g in query)
                Console.WriteLine(string.Format("{0} 年龄:{1} 电话:{2}", g.Name, g.Age, g.Tel));

            Console.ReadKey();
        }
    }
}

3.9  join
using System;
using System.Collections.Generic;
using System.Linq;

namespace DemoLinq
{
    class Program
    {
        static void Main(string[] args)
        {
            //初始化客户集合
            List<GuestInfo> gList = new List<GuestInfo>()
            {
                new GuestInfo
                {
                    Name = "林晚荣",
                    Age = 21,
                    Tel = "026*-888888**" },
                new GuestInfo
                {
                    Name = "肖青漩",
                    Age = 21,
                    Tel = "017*-876543**"
                },
                new GuestInfo
                {
                    Name = "董巧巧",
                    Age = 19,
                    Tel = "029*-981256**"
                },
                 new GuestInfo
                {
                    Name = "徐芷晴",
                    Age = 24,
                    Tel = "089*-569832**"
                }
            };

            ///初始化客户职务集合
            List<GuestTitle> titleList = new List<GuestTitle>()
            {
                new GuestTitle{ Name = "林晚荣", Tilte = "金刀汉王"},
                new GuestTitle{ Name = "林晚荣", Tilte = "天下第一丁"},
                new GuestTitle{ Name = "肖青漩", Tilte = "出云公主"},
                new GuestTitle{ Name = "董巧巧", Tilte = "酒店CEO"},
                new GuestTitle{ Name = "董巧巧", Tilte = "乖巧人儿"}
            };

            Console.WriteLine("内部联接");
            //根据姓名进行内部联接
            var query = from guest in gList
                        join title in titleList on guest.Name equals title.Name
                        select new { Name = guest.Name, Title = title.Tilte, Age = guest.Age };


            foreach (var g in query)
                Console.WriteLine(string.Format("{0} {1} 年龄:{2}", g.Title, g.Name, g.Age));


            Console.WriteLine("\n根据姓名进行分组联接");

            //根据姓名进行分组联接
            var query2 = from guest in gList
                         join title in titleList on guest.Name equals title.Name into tgroup
                         select new { Name = guest.Name, Titles = tgroup };

            foreach (var g in query2)
            {
                Console.WriteLine(g.Name);
                foreach (var g2 in g.Titles)
                    Console.WriteLine(string.Format("   {0}", g2.Tilte));
            }


            Console.WriteLine("\n左外部联接");
            //根据姓名进行左外部联接
            var query3 = from guest in gList
                         join title in titleList on guest.Name equals title.Name into tgroup
                         from subtitle in tgroup.DefaultIfEmpty()
                         select new { Name = guest.Name, Title = (subtitle == null ? "空缺" : subtitle.Tilte)} ;

            foreach (var g in query3)
                Console.WriteLine(string.Format("{0} {1}", g.Title, g.Name));

            Console.ReadKey();

        }
    }
}

四、用于集合、文件、字符串对象的LINQ(LINQ  to  Objects)

4.1 Take Method
using System;
using System.Linq;
using System.Collections.Generic;

namespace DemoTake
{
    class Program
    {
        static void Main(string[] args)
        {
            //定义数组
            string[] nemes = { "林晚荣", "洛凝", "董巧巧", "依莲", "安碧如" };

            Console.WriteLine("Take方法直接输出前3个元素");
            //用Take方法直接输出前3个元素
            foreach (string s in nemes.Take(3))
                Console.WriteLine(s);

            var query = from n in nemes
                        where n.Length == 2
                        select n;

            Console.WriteLine("\n用Take方法输出查询结果的前1个元素");

            //用Take方法输出查询结果的前1个元素
            foreach (string s in query.Take(1))
                Console.WriteLine(s);

            Console.ReadKey();
        }
    }
}

4.2 TakeWhile

using System;
using System.Linq;

namespace DemoTakeWhile1
{
    class Program
    {
        static void Main(string[] args)
        {
            //定义数组
            string[] nemes = { "依莲", "董巧巧","洛凝", "安碧如" };

            var takenames = nemes.TakeWhile(n => n.Length == 2);

            //输出字数是2个的名字
            foreach (var s in takenames)
                Console.WriteLine(s);

            Console.ReadKey();
        }
    }
}
using System;
using System.Linq;

namespace DemoTakeWhile2
{
    class Program
    {
        static void Main(string[] args)
        {
            //定义数组
            string[] nemes = { "林晚荣", "洛凝", "董巧巧","出云公主", "依莲", "安碧如" };


            //返回元素字数小于4并且索引小于5的元素
            var takenames = nemes.TakeWhile((n, i) => n.Length < 4 && i < 5);
            foreach (string s in takenames)
                Console.WriteLine(s);


            Console.ReadKey();
        }
    }
}


4.4 skip
using System;
using System.Linq;

namespace DemoSkip
{
    class Program
    {
        static void Main(string[] args)
        {
            //定义数组
            string[] nemes = { "林晚荣", "洛凝", "董巧巧", "依莲", "安碧如" };

            Console.WriteLine("用Skip方法跳过前3个元素后输出");
            //用Skip方法跳过前3个元素后输出
            foreach (string s in nemes.Skip(3))
                Console.WriteLine(s);

            var query = from n in nemes
                        where n.Length == 3
                        select n;

            Console.WriteLine("\n用Skip方法跳过第一个查询结果后输出");

            //用Skip方法跳过第一个查询结果后输出
            foreach (string s in query.Skip(1))
                Console.WriteLine(s);

            Console.ReadKey();
        }
    }
}

4.5 SkipWhile
using System;
using System.Linq;

namespace DemoSkipWhile2
{
    class Program
    {
        static void Main(string[] args)
        {
            //定义数组
            string[] nemes = { "林晚荣", "洛凝", "董巧巧", "出云公主", "依莲", "安碧如" };


            //跳过元素字数小于4并且索引小于5的元素
            var takenames = nemes.SkipWhile((n, i) => n.Length < 4 && i < 5);
            foreach (string s in takenames)
                Console.WriteLine(s);

            Console.ReadKey();
        }
    }
}

4.6  Take、TakeWhile\ Skip\ SkipWhile
利用Take 和Skip实现分页
using System;
using System.Linq;

namespace DemoPaginate
{
    class Program
    {
        static void Main(string[] args)
        {
            //当前页码
            int ipage = 0;
            //每页记录数
            int ipagesize = 2;

            //定义数组
            string[] nemes = { "林晚荣", "洛凝", "董巧巧", "出云公主", "依莲", "安碧如" };

            Console.WriteLine(string.Format("输出第 {0} 页记录", ipage));
            //输出第 0 页记录
            var q = nemes.Skip(ipagesize * ipage).Take(ipagesize);
            foreach (string s in q)
                Console.WriteLine(s);

            ipage++;
            Console.WriteLine(string.Format("\n输出第 {0} 页记录", ipage));
            //输出第 1 页记录
            var q2 = nemes.Skip(ipagesize * ipage).Take(ipagesize);
            foreach (string s in q2)
                Console.WriteLine(s);

            ipage++;
            Console.WriteLine(string.Format("\n输出第 {0} 页记录", ipage));
            //输出第 2 页记录
            var q3 = nemes.Skip(ipagesize * ipage).Take(ipagesize);
            foreach (string s in q3)
                Console.WriteLine(s);

            Console.ReadKey();


        }
    }
}
4.8 Reverse

using System;
using System.Linq;

namespace DemoReverse
{
    class Program
    {
        static void Main(string[] args)
        {
            string str = "Reverse方法，用于反转序列中元素的顺序。";

            Console.WriteLine(str);

            Console.WriteLine("\n反转字符串\n");

            var strrev = str.ToCharArray().Reverse();

            foreach (var c in strrev)
                Console.Write(c);

            Console.ReadKey();
        }
    }
}

4.9 Distinct
using System;
using System.Linq;

namespace DemoDistinct1
{
    class Program
    {
        static void Main(string[] args)
        {
            ///定义一个有重复元素的数组
            string[] girls = { "萧玉若", "洛凝", "萧玉霜", "秦仙儿",
                               "月牙儿", "秦仙儿", "洛凝", "萧玉霜"};

            Console.WriteLine("含有重复元素的数组");
            foreach (var g in girls)
                Console.Write(string.Format("{0} ", g));

            var q = girls.Distinct();

            Console.WriteLine("\n\n去除重复元素的序列");
            foreach (var g in q)
                Console.Write(string.Format("{0} ", g));

            Console.ReadKey();
        }
    }
}
4.10  Distinct

using System.Collections.Generic;

namespace DemoDistinct2
{
    /// <summary>
    /// 自定义相等比较器
    /// </summary>
    public class MyEqualityComparer<T>: IEqualityComparer<T>
    {

        #region IEqualityComparer<T> 成员

        public bool Equals(T x, T y)
        {
            string stmp = x as string;

            if (stmp != null)
            {
                if (stmp == "萧玉霜")
                    return false;
            }

            if (x.GetHashCode() == y.GetHashCode())
                return true;
            else
                return false;
        }

        public int GetHashCode(T obj)
        {
            return obj.GetHashCode();
        }

        #endregion
    }
}

4.11 Union
using System;
using System.Linq;

namespace DemoDistinct2
{
    class Program
    {
        static void Main(string[] args)
        {
            ///定义一个有重复元素的数组
            string[] girls = { "萧玉若", "洛凝", "萧玉霜", "秦仙儿",
                               "月牙儿", "萧玉霜","秦仙儿", "洛凝", "萧玉霜"};

            Console.WriteLine("含有重复元素的数组");
            foreach (var g in girls)
                Console.Write(string.Format("{0} ", g));

            var q = girls.Distinct(new MyEqualityComparer<string>());

            Console.WriteLine("\n\n去除重复元素的序列");
            foreach (var g in q)
                Console.Write(string.Format("{0} ", g));

            Console.ReadKey();
        }
    }
}


4.12 union
using System;
using System.Linq;
using DemoDistinct2;

namespace DemoUnion2
{
    class Program
    {
        static void Main(string[] args)
        {
            ///定义数组
            string[] girls1 = { "萧玉若", "洛凝", "萧玉霜", "秦仙儿" };
            string[] girls2 = { "月牙儿", "秦仙儿", "洛凝", "萧玉霜" };

            var girls = girls1.Union(girls2,new MyEqualityComparer<string>());

            Console.WriteLine("合并后的序列");
            foreach (var g in girls)
                Console.Write(string.Format("{0} ", g));

            Console.ReadKey();
        }
    }
}

4.13 Concat


using System;
using System.Linq;

namespace DemoConcat
{
    class Program
    {
        static void Main(string[] args)
        {
            ///定义数组
            string[] girls1 = { "萧玉若", "洛凝", "萧玉霜", "秦仙儿" };
            string[] girls2 = { "月牙儿", "秦仙儿", "洛凝", "萧玉霜" };

            var girls = girls1.Concat(girls2);

            Console.WriteLine("合并后的序列");
            foreach (var g in girls)
                Console.Write(string.Format("{0} ", g));

            Console.ReadKey();
        }
    }
}

4.14 Intersect
using System;
using System.Linq;

namespace DemoIntersect1
{
    class Program
    {
        static void Main(string[] args)
        {
            ///定义数组
            string[] girls1 = { "萧玉若", "洛凝", "萧玉霜", "秦仙儿" };
            string[] girls2 = { "月牙儿", "秦仙儿", "洛凝", "萧玉霜" };

            var girls = girls1.Intersect(girls2);

            Console.WriteLine("在2个数组中都存在的元素序列");
            foreach (var g in girls)
                Console.Write(string.Format("{0} ", g));

            Console.ReadKey();
        }
    }
}

4.15 使用自定义比较器找出两个数组汇总相同的元素

using System.Collections.Generic;

namespace DemoDistinct2
{
    /// <summary>
    /// 自定义相等比较器
    /// </summary>
    public class MyEqualityComparer<T>: IEqualityComparer<T>
    {

        #region IEqualityComparer<T> 成员

        public bool Equals(T x, T y)
        {
            string stmp = x as string;

            if (stmp != null)
            {
                if (stmp == "萧玉霜")
                    return false;
            }

            if (x.GetHashCode() == y.GetHashCode())
                return true;
            else
                return false;
        }

        public int GetHashCode(T obj)
        {
            return obj.GetHashCode();
        }

        #endregion
    }
}
using System;
using System.Linq;
using DemoDistinct2;

namespace DemoIntersect2
{
    class Program
    {
        static void Main(string[] args)
        {
            ///定义数组
            string[] girls1 = { "萧玉若", "洛凝", "萧玉霜", "秦仙儿" };
            string[] girls2 = { "月牙儿", "秦仙儿", "洛凝", "萧玉霜" };

            var girls = girls1.Intersect(girls2,new MyEqualityComparer<string>());

            Console.WriteLine("在2个数组中都存在的元素序列");
            foreach (var g in girls)
                Console.Write(string.Format("{0} ", g));

            Console.ReadKey();
        }
    }
}


4.16 找出两个数组中不同的元素 Except
using System;
using System.Linq;

namespace DemoExcept1
{
    class Program
    {
        static void Main(string[] args)
        {
             ///定义数组
            string[] girls1 = { "萧玉若", "洛凝", "萧玉霜", "秦仙儿" };
            string[] girls2 = { "月牙儿", "秦仙儿", "洛凝", "萧玉霜" };

            var girls = girls1.Except(girls2);

            Console.WriteLine("2个数组中不同元素");
            foreach (var g in girls)
                Console.Write(string.Format("{0} ", g));

            Console.ReadKey();
        }
    }
}
4.17 使用自定义比较器找出两个数组中不同的元素Except
using System;
using System.Linq;
using DemoDistinct2;

namespace DemoExcept2
{
    class Program
    {
        static void Main(string[] args)
        {
            ///定义数组
            string[] girls1 = { "萧玉若", "洛凝", "萧玉霜", "秦仙儿" };
            string[] girls2 = { "月牙儿", "秦仙儿", "洛凝", "萧玉霜" };

            var girls = girls1.Except(girls2, new MyEqualityComparer<string>());

            Console.WriteLine("2个数组中不同元素");
            foreach (var g in girls)
                Console.Write(string.Format("{0} ", g));

            Console.ReadKey();
        }
    }
}
4.18  Range
using System;
using System.Linq;

namespace DemoRange
{
    class Program
    {
        static void Main(string[] args)
        {
            //起始页码
            int istart = 18;

            //结束页码
            int iend = 26;

            var pages = Enumerable.Range(istart, iend - istart + 1);

            Console.WriteLine("输出页码");
            foreach (var n in pages)
                Console.Write(string.Format("[{0}] ", n));

            Console.ReadKey();
        }
    }
}
4.19 生成含有5个相同类型元素的序列
using System;
using System.Linq;

namespace DemoRepeat
{
    class Program
    {
        static void Main(string[] args)
        {
            ///定义一个匿名类型
            var orange = new {Color="橘色",Name="桔子"};

            var oranges = Enumerable.Repeat(orange,5);

            Console.WriteLine("包含5个匿名类型的元素");
            foreach (var n in oranges)
                Console.WriteLine(string.Format("{0}的{1} ", n.Color, n.Name));

            Console.ReadKey();
        }
    }
}

4.20 生成String 类型的空序列
using System;
using System.Collections.Generic;
using System.Linq;

namespace DemoEmpty
{
    class Program
    {
        static void Main(string[] args)
        {

            IEnumerable<string> empty = Enumerable.Empty<string>();

            Console.WriteLine(string.Format("序列元素数：{0}",empty.Count()));

            Console.ReadKey();
        }
    }
}

4.21 检测多种类型序列是否为空DefaultIfEmpty
using System;
using System.Linq;

namespace DemoDefaultIfEmpty
{
    class Program
    {
        static void Main(string[] args)
        {
            //定义数组
            string[] nemes = { "林晚荣", "洛凝", "董巧巧", "依莲", "安碧如" };
            //空的int类型序列
            var intempty = Enumerable.Empty<int>();

            //没有找的元素的序列
            var empty = from n in nemes
                        where n == "宁雨昔"
                        select n;

            Console.WriteLine("DefaultIfEmpty 返回有内容的序列");
            foreach (string s in nemes.DefaultIfEmpty())
                Console.Write(string.Format("{0} ", s));


            Console.WriteLine(string.Format("\nempty 空序列元素数：{0}", intempty.Count()));

            Console.WriteLine(string.Format("empty 空序列应用DefaultIfEmpty方法后的元素数：{0}", empty.DefaultIfEmpty().Count()));

            Console.Write(string.Format("empty 空序列应用DefaultIfEmpty方法后的元素值："));
            foreach (var s in empty.DefaultIfEmpty())
                if (s == null)
                    Console.Write("null");


            Console.WriteLine("\n\n****************************************\n");

            Console.WriteLine(string.Format("intempty 空序列元素数：{0}", intempty.Count()));

            Console.WriteLine(string.Format("intempty 空序列应用DefaultIfEmpty方法后的元素数：{0}", intempty.DefaultIfEmpty().Count()));

            Console.Write(string.Format("intempty 空序列应用DefaultIfEmpty方法后的元素值："));
            foreach (var s in intempty.DefaultIfEmpty())
                Console.Write(s);

            Console.ReadKey();
        }
    }
}

4.23 ArrayList 序列转换成泛型序列

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;

namespace DemoCast
{
    class Program
    {
        static void Main(string[] args)
        {
            //定义ArrayList
            //由于ArrayList没有实现泛型IEnumerable<T>接口，
            //所以无法用集合初始化器
            ArrayList nemes = new ArrayList();
            nemes.Add( "林晚荣");
            nemes.Add( "洛凝");
            nemes.Add( "董巧巧");
            nemes.Add( "依莲");

            IEnumerable<string> newnames = nemes.Cast<string>();

            foreach (string s in newnames)
                Console.Write(string.Format("{0} ",s));

            Console.ReadKey();
        }
    }
}

4.24 OfType 方法
用OfType方法转换ArrayList序列转换成泛型序列
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;

namespace DemoOfType
{
    class Program
    {
        static void Main(string[] args)
        {
            //定义ArrayList
            ArrayList nemes = new ArrayList();
            nemes.Add("林晚荣");
            nemes.Add("洛凝");
            nemes.Add(100);
            nemes.Add(new Stack());
            nemes.Add("董巧巧");

            IEnumerable<string> newnames = nemes.OfType<string>();

            foreach (string s in newnames)
                Console.Write(string.Format("{0} ", s));

            Console.ReadKey();
        }
    }
}

4.25 将IQueryable 类型转换为IEnumerable类型

4.26用于立即执行的Enumerable类方法成员
using System;
using System.Collections.Generic;
using System.Linq;

namespace DemoToArray
{
    class Program
    {
        static void Main(string[] args)
        {
            ///定义List
            List<string> lst = new List<string>{ "出云公主", "乖巧人儿", "萧家二小姐", "霓裳公主" };

            var query = from t in lst
                        where t.IndexOf("公主") > -1
                        select t;

            string[] strarray = query.ToArray();

            Console.WriteLine(string.Format("lst 类型：{0}", lst.GetType().Name));
            Console.WriteLine(string.Format("query 类型：{0}", query.GetType().Name));
            Console.WriteLine(string.Format("strarray 类型：{0}", strarray.GetType().Name));

            Console.Write("\nstrarray 内容：");
            foreach (string s in strarray)
                Console.Write(string.Format(" {0}", s));

            Console.ReadKey();
        }
    }
}

4.27 将序列转换为泛型List<T>-------ToList

using System;
using System.Collections.Generic;
using System.Linq;

namespace DemoToList
{
    class Program
    {
        static void Main(string[] args)
        {
            ///定义数组
            string[] strarray = { "出云公主", "乖巧人儿", "萧家二小姐", "霓裳公主" };

            var query = from t in strarray
                        where t.IndexOf("公主") > -1
                        select t;

            List<string> lst = query.ToList();

            Console.WriteLine(string.Format("strarray 类型：{0}", strarray.GetType().Name));
            Console.WriteLine(string.Format("query 类型：{0}", query.GetType().Name));
            Console.WriteLine(string.Format("lst 类型：{0}", lst.GetType().Name));

            Console.Write("\nlst 内容：");
            foreach (string s in lst)
                Console.Write(string.Format(" {0}", s));

            Console.ReadKey();
        }
    }
}

4.28 ToDictionary
using System;
using System.Collections.Generic;
using System.Linq;
using DemoLinq;

namespace DemoToDictionary1
{
    class Program
    {
        static void Main(string[] args)
        {
            //初始化集合
            List<GuestInfo> gList = new List<GuestInfo>()
            {
                new GuestInfo
                {
                    Name = "萧玉霜",
                    Age = 17,
                    Tel = "053*-985690**" },
                new GuestInfo
                {
                    Name = "萧玉若",
                    Age = 21,
                    Tel = "035*-120967**"
                },
                new GuestInfo
                {
                    Name = "徐长今",
                    Age = 18,
                    Tel = "039*-967512**"
                },
                new GuestInfo
                {
                    Name = "徐芷晴",
                    Age = 24,
                    Tel = "089*-569832**"
                }
            };


            //使用Tel属性作为Dictionary的键值
            Dictionary<string, GuestInfo> dictionary = gList.ToDictionary(guest => guest.Tel);

            Console.WriteLine(string.Format("gList 类型：{0}", gList.GetType().Name));
            Console.WriteLine(string.Format("dictionary 类型：{0}", dictionary.GetType().Name));

            Console.WriteLine("\ndictionary 内容：");
            foreach (string s in dictionary.Keys)
                Console.WriteLine(string.Format("键值：{0}，姓名：{1}", s, dictionary[s].Name));

            Console.ReadKey();

        }
    }
}

using System.Collections.Generic;

namespace DemoDistinct2
{
    /// <summary>
    /// 自定义相等比较器
    /// </summary>
    public class MyEqualityComparer<T>: IEqualityComparer<T>
    {

        #region IEqualityComparer<T> 成员

        public bool Equals(T x, T y)
        {
            string stmp = x as string;

            if (stmp != null)
            {
                if (stmp == "萧玉霜")
                    return false;
            }

            if (x.GetHashCode() == y.GetHashCode())
                return true;
            else
                return false;
        }

        public int GetHashCode(T obj)
        {
            return obj.GetHashCode();
        }

        #endregion
    }
}
using System;
using System.Collections.Generic;
using System.Linq;
using DemoDistinct2;
using DemoLinq;

namespace DemoToDictionary2
{
    class Program
    {
        static void Main(string[] args)
        {
            //初始化集合
            List<GuestInfo> gList = new List<GuestInfo>()
            {
                new GuestInfo
                {
                    Name = "萧玉霜",
                    Age = 17,
                    Tel = "053*-985690**" },
                new GuestInfo
                {
                    Name = "萧玉若",
                    Age = 21,
                    Tel = "035*-120967**"
                },
                new GuestInfo
                {
                    Name = "徐长今",
                    Age = 18,
                    Tel = "039*-967512**"
                },
                new GuestInfo
                {
                    Name = "徐芷晴",
                    Age = 24,
                    Tel = "089*-569832**"
                }
            };


            //使用Name属性作为Dictionary的键值
            Dictionary<string, GuestInfo> dictionary = gList.ToDictionary(guest => guest.Name,new MyEqualityComparer<string>());

            Console.WriteLine(string.Format("gList 类型：{0}", gList.GetType().Name));
            Console.WriteLine(string.Format("dictionary 类型：{0}", dictionary.GetType().Name));

            Console.WriteLine("\n检查是否有不能通过键值访问的元素");
            foreach (var s in dictionary)
            {
                if(!dictionary.Keys.Contains(s.Key))
                    Console.WriteLine(string.Format("键值为 {0} 的内容，不能通过键值访问。", s.Key));
            }

            Console.WriteLine("\n遍历dictionary全部的元素");
            foreach (var s in dictionary)
                Console.WriteLine(string.Format("键值：{0}，电话：{1}", s.Key, s.Value.Tel));

            Console.ReadKey();

        }
    }
}
using System;
using System.Collections.Generic;
using System.Linq;
using DemoLinq;

namespace DemoToDictionary3
{
    class Program
    {
        static void Main(string[] args)
        {
            //初始化集合
            List<GuestInfo> gList = new List<GuestInfo>()
            {
                new GuestInfo
                {
                    Name = "萧玉霜",
                    Age = 17,
                    Tel = "053*-985690**" },
                new GuestInfo
                {
                    Name = "萧玉若",
                    Age = 21,
                    Tel = "035*-120967**"
                },
                new GuestInfo
                {
                    Name = "徐长今",
                    Age = 18,
                    Tel = "039*-967512**"
                },
                new GuestInfo
                {
                    Name = "徐芷晴",
                    Age = 24,
                    Tel = "089*-569832**"
                }
            };


            //使用Tel属性作为Dictionary的键值,Name属性作为Value值
            Dictionary<string, string> dictionary = gList.ToDictionary(guest => guest.Tel,
                g=>g.Name);

            Console.WriteLine(string.Format("gList 类型：{0}", gList.GetType().Name));
            Console.WriteLine(string.Format("dictionary 类型：{0}", dictionary.GetType().Name));

            Console.WriteLine("\ndictionary 内容：");
            foreach (string s in dictionary.Keys)
                Console.WriteLine(string.Format("键值：{0}，姓名：{1}", s, dictionary[s]));

            Console.ReadKey();

        }
    }
}
using System;
using System.Collections.Generic;
using System.Linq;
using DemoDistinct2;
using DemoLinq;

namespace DemoToDictionary4
{
    class Program
    {
        static void Main(string[] args)
        {
            //初始化集合
            List<GuestInfo> gList = new List<GuestInfo>()
            {
                new GuestInfo
                {
                    Name = "萧玉霜",
                    Age = 17,
                    Tel = "053*-985690**" },
                new GuestInfo
                {
                    Name = "萧玉若",
                    Age = 21,
                    Tel = "035*-120967**"
                },
                new GuestInfo
                {
                    Name = "徐长今",
                    Age = 18,
                    Tel = "039*-967512**"
                },
                new GuestInfo
                {
                    Name = "徐芷晴",
                    Age = 24,
                    Tel = "089*-569832**"
                }
            };


            //使用Name属性作为Dictionary的键值，Tel属性作为Value值
            Dictionary<string, string> dictionary = gList.ToDictionary(guest => guest.Name,g => g.Tel, new MyEqualityComparer<string>());

            Console.WriteLine(string.Format("gList 类型：{0}", gList.GetType().Name));
            Console.WriteLine(string.Format("dictionary 类型：{0}", dictionary.GetType().Name));

            Console.WriteLine("\n检查是否有不能通过键值访问的元素");
            foreach (var s in dictionary)
            {
                if (!dictionary.Keys.Contains(s.Key))
                    Console.WriteLine(string.Format("键值为 {0} 的内容，不能通过键值访问。", s.Key));
            }

            Console.WriteLine("\n遍历dictionary全部的元素");
            foreach (var s in dictionary)
                Console.WriteLine(string.Format("键值：{0}，电话：{1}", s.Key, s.Value));

            Console.ReadKey();

        }
    }
}

4.32 List<GuestInfo>转换为Lookup<string,GuestInfo>类型
Lookup 有些像类型转换后的分组操作

using System;
using System.Collections.Generic;
using System.Linq;
using DemoLinq;

namespace DemoToLookup1
{
    class Program
    {
        static void Main(string[] args)
        {
            //初始化集合
            List<GuestInfo> gList = new List<GuestInfo>()
            {
                new GuestInfo
                {
                    Name = "萧玉霜",
                    Age = 17,
                    Tel = "053*-985690**" },
                new GuestInfo
                {
                    Name = "萧玉若",
                    Age = 21,
                    Tel = "035*-120967**"
                },
                new GuestInfo
                {
                    Name = "徐长今",
                    Age = 18,
                    Tel = "039*-967512**"
                },
                new GuestInfo
                {
                    Name = "徐芷晴",
                    Age = 24,
                    Tel = "089*-569832**"
                }
            };


            //使用姓作为Lookup的键值
            ILookup<string, GuestInfo> lookup = gList.ToLookup(guest => guest.Name.Substring(0,1));

            Console.WriteLine(string.Format("gList 类型：{0}", gList.GetType().Name));
            Console.WriteLine(string.Format("lookup 类型：{0}", lookup.GetType().Name));

            Console.WriteLine("\nlookup 内容：");
            foreach (var k in lookup)
            {
                Console.WriteLine(string.Format("键值：{0}", k.Key));
                foreach (var v in k)
                    Console.WriteLine(string.Format("姓名：{0}，年龄：{1}", v.Name,v.Age));

                Console.WriteLine("****************************");
            }
            Console.ReadKey();
        }
    }
}

using System.Collections.Generic;

namespace DemoDistinct2
{
    /// <summary>
    /// 自定义相等比较器
    /// </summary>
    public class MyEqualityComparer<T>: IEqualityComparer<T>
    {

        #region IEqualityComparer<T> 成员

        public bool Equals(T x, T y)
        {
            string stmp = x as string;

            if (stmp != null)
            {
                if (stmp == "萧")
                    return false;
            }

            if (x.GetHashCode() == y.GetHashCode())
                return true;
            else
                return false;
        }

        public int GetHashCode(T obj)
        {
            return obj.GetHashCode();
        }

        #endregion
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using DemoDistinct2;
using DemoLinq;

namespace DemoToLookup2
{
    class Program
    {
        static void Main(string[] args)
        {
            //初始化集合
            List<GuestInfo> gList = new List<GuestInfo>()
            {
                new GuestInfo
                {
                    Name = "萧玉霜",
                    Age = 17,
                    Tel = "053*-985690**" },
                new GuestInfo
                {
                    Name = "萧玉若",
                    Age = 21,
                    Tel = "035*-120967**"
                },
                new GuestInfo
                {
                    Name = "徐长今",
                    Age = 18,
                    Tel = "039*-967512**"
                },
                new GuestInfo
                {
                    Name = "徐芷晴",
                    Age = 24,
                    Tel = "089*-569832**"
                }
            };


            //使用姓作为Lookup的键值
            ILookup<string, GuestInfo> lookup = gList.ToLookup(guest => guest.Name.Substring(0, 1), new MyEqualityComparer<string>());

            Console.WriteLine(string.Format("gList 类型：{0}", gList.GetType().Name));
            Console.WriteLine(string.Format("lookup 类型：{0}", lookup.GetType().Name));

            Console.WriteLine("\nlookup 内容：");
            foreach (var k in lookup)
            {
                Console.WriteLine(string.Format("键值：{0}", k.Key));
                foreach (var v in k)
                    Console.WriteLine(string.Format("姓名：{0}，年龄：{1}", v.Name, v.Age));

                Console.WriteLine("****************************");
            }
            Console.ReadKey();
        }
    }
}


using System;
using System.Collections.Generic;
using System.Linq;
using DemoLinq;

namespace DemoLookup3
{
    class Program
    {
        static void Main(string[] args)
        {
            //初始化集合
            List<GuestInfo> gList = new List<GuestInfo>()
            {
                new GuestInfo
                {
                    Name = "萧玉霜",
                    Age = 17,
                    Tel = "053*-985690**" },
                new GuestInfo
                {
                    Name = "萧玉若",
                    Age = 21,
                    Tel = "035*-120967**"
                },
                new GuestInfo
                {
                    Name = "徐长今",
                    Age = 18,
                    Tel = "039*-967512**"
                },
                new GuestInfo
                {
                    Name = "徐芷晴",
                    Age = 24,
                    Tel = "089*-569832**"
                }
            };


            //使用姓作为Lookup的键值Value值为Name属性
            ILookup<string, string> lookup = gList.ToLookup(guest => guest.Name.Substring(0, 1),g=>g.Name);

            Console.WriteLine(string.Format("gList 类型：{0}", gList.GetType().Name));
            Console.WriteLine(string.Format("lookup 类型：{0}", lookup.GetType().Name));

            Console.WriteLine("\nlookup 内容：");
            foreach (var k in lookup)
            {
                Console.WriteLine(string.Format("键值：{0}", k.Key));
                foreach (var v in k)
                    Console.WriteLine(string.Format("姓名：{0}", v));

                Console.WriteLine("****************************");
            }
            Console.ReadKey();
        }
    }
}


using System.Collections.Generic;

namespace DemoDistinct2
{
    /// <summary>
    /// 自定义相等比较器
    /// </summary>
    public class MyEqualityComparer<T>: IEqualityComparer<T>
    {

        #region IEqualityComparer<T> 成员

        public bool Equals(T x, T y)
        {
            string stmp = x as string;

            if (stmp != null)
            {
                if (stmp == "萧")
                    return false;
            }

            if (x.GetHashCode() == y.GetHashCode())
                return true;
            else
                return false;
        }

        public int GetHashCode(T obj)
        {
            return obj.GetHashCode();
        }

        #endregion
    }
}
using System;
using System.Collections.Generic;
using System.Linq;
using DemoDistinct2;
using DemoLinq;

namespace DemoToLookup4
{
    class Program
    {
        static void Main(string[] args)
        {
            //初始化集合
            List<GuestInfo> gList = new List<GuestInfo>()
            {
                new GuestInfo
                {
                    Name = "萧玉霜",
                    Age = 17,
                    Tel = "053*-985690**" },
                new GuestInfo
                {
                    Name = "萧玉若",
                    Age = 21,
                    Tel = "035*-120967**"
                },
                new GuestInfo
                {
                    Name = "徐长今",
                    Age = 18,
                    Tel = "039*-967512**"
                },
                new GuestInfo
                {
                    Name = "徐芷晴",
                    Age = 24,
                    Tel = "089*-569832**"
                }
            };


            //使用姓作为Lookup的键值Name属性作为Value
            ILookup<string, string> lookup = gList.ToLookup(guest => guest.Name.Substring(0, 1),g=>g.Name,new MyEqualityComparer<string>());

            Console.WriteLine(string.Format("gList 类型：{0}", gList.GetType().Name));
            Console.WriteLine(string.Format("lookup 类型：{0}", lookup.GetType().Name));

            Console.WriteLine("\nlookup 内容：");
            foreach (var k in lookup)
            {
                Console.WriteLine(string.Format("键值：{0}", k.Key));
                foreach (var v in k)
                    Console.WriteLine(string.Format("姓名：{0}", v));

                Console.WriteLine("****************************");
            }

            Console.ReadKey();
        }
    }
}

4.36 SequenceEqual
比较两个序列是否相等
using System;
using System.Linq;

namespace DemoSequenceEqual1
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] lst1 = { "出云公主", "乖巧人儿", "萧家二小姐", "霓裳公主" };
            string[] lst2 = { "出云公主", "乖巧人儿", "萧家二小姐", "霓裳公主" };
            string[] lst3 = { "乖巧人儿", "出云公主", "萧家二小姐", "霓裳公主" };

            Console.WriteLine(string.Format("lst1 和 lst2 对比结果：{0}", lst1.SequenceEqual(lst2)));

            Console.WriteLine(string.Format("lst1 和 lst3 对比结果：{0}", lst1.SequenceEqual(lst3)));

            Console.ReadKey();
        }
    }
}

4.37 使用自定义比较器比较两个序列是否相等
using System.Collections.Generic;
using System.Linq;

namespace DemoSequenceEqual2
{
    /// <summary>
    /// 自定义string数组比较器
    /// </summary>
    public class MyEqualityComparer2<T> : IEqualityComparer<T>
    {
        private string[] sec;
        public MyEqualityComparer2(string[] s)
        {
            this.sec = s;
        }

        #region IEqualityComparer<T> 成员

        public bool Equals(T x, T y)
        {
            string stmp = x as string;

            if (stmp != null)
            {
                return sec.Contains(stmp);
            }

            return false;
        }

        public int GetHashCode(T obj)
        {
            return obj.GetHashCode();
        }

        #endregion
    }
}

using System;
using System.Linq;

namespace DemoSequenceEqual2
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] lst1 = { "出云公主", "乖巧人儿", "萧家二小姐", "霓裳公主" };
            string[] lst3 = { "乖巧人儿", "出云公主", "萧家二小姐", "霓裳公主" };

            Console.WriteLine(string.Format("lst1 和 lst3 对比结果：{0}", lst1.SequenceEqual(lst3,
                new MyEqualityComparer2<string>(lst3))));

            Console.ReadKey();
        }
    }
}

4.38 First 第一个输出

using System;
using System.Linq;

namespace DemoFirst1
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] lst = { "出云公主", "乖巧人儿", "萧家二小姐", "霓裳公主" };

            var item = lst.First();

            Console.WriteLine(string.Format("数组的第一个元素：{0}", item));

            Console.ReadKey();
        }
    }
}
using System;
using System.Linq;

namespace DemoFirst2
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] lst = { "乖巧人儿", "霓裳公主", "萧家二小姐", "出云公主" };

            var item = lst.First(str=>str.IndexOf("公主")>-1);

            Console.WriteLine(string.Format("数组的第一个符合条件的元素：{0}", item));

            Console.ReadKey();
        }
    }
}

4.40 返回序列中第一元素，如果未找到，返回类型默认值
FirstOrDefault
using System;
using System.Linq;

namespace DemoFirstOrDefault1
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] lst = { "出云公主", "乖巧人儿", "萧家二小姐", "霓裳公主" };
            int[] lst2 = { };

            var item = lst.FirstOrDefault();
            var item2 = lst2.FirstOrDefault();

            Console.WriteLine(string.Format("lst数组的第一个元素：{0}", item));
            Console.WriteLine(string.Format("lst2数组的第一个元素：{0}", item2));

            Console.ReadKey();
        }
    }
}


using System;
using System.Linq;

namespace DemoFirstOrDefault2
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] lst = { 10,20,30,40,50,100 };

            var item = lst.FirstOrDefault(i => i==66);

            Console.WriteLine(string.Format("数组的第一个符合条件的元素：{0}", item));

            Console.ReadKey();
        }
    }
}

4.42 返回序列中最后一个元素 Last
using System;
using System.Linq;

namespace DemoLast1
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] lst = { "出云公主", "乖巧人儿", "萧家二小姐", "霓裳公主" };

            var item = lst.Last();

            Console.WriteLine(string.Format("数组的最后一个元素：{0}", item));

            Console.ReadKey();
        }
    }
}

using System;
using System.Linq;

namespace DemoLast2
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] lst = { "乖巧人儿", "霓裳公主", "萧家二小姐", "出云公主" };

            var item = lst.Last(str => str.IndexOf("公主") > -1);

            Console.WriteLine(string.Format("数组的最后一个符合条件的元素：{0}", item));

            Console.ReadKey();
        }
    }
}


4.44 LastOrDefault 方法

using System;
using System.Linq;

namespace DemoLastOrDefault1
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] lst = { "出云公主", "乖巧人儿", "萧家二小姐", "霓裳公主" };
            int[] lst2 = { };

            var item = lst.LastOrDefault();
            var item2 = lst2.LastOrDefault();

            Console.WriteLine(string.Format("lst数组的最后一个元素：{0}", item));
            Console.WriteLine(string.Format("lst2数组的最后一个元素：{0}", item2));

            Console.ReadKey();
        }
    }
}

using System;
using System.Linq;

namespace DemoLastOrDefault2
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] lst = { 10, 20, 30, 40, 50, 100 };

            var item = lst.LastOrDefault(i => i == 66);

            Console.WriteLine(string.Format("数组的最后一个符合条件的元素：{0}", item));

            Console.ReadKey();
        }
    }
}

4.46 返回空序列的唯一元素Single
using System;
using System.Linq;

namespace DemoSingle1
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] lst = { "乖巧人儿" };
            string[] lst2 = { "出云公主", "乖巧人儿", "萧家二小姐", "霓裳公主" };

            var item = lst.Single();

            try
            {
                var itme2 = lst2.Single();
            }
            catch (Exception e)
            {
                Console.WriteLine(string.Format("lst2应用Single方法出错：{0}", e.Message));
            }

            Console.WriteLine(string.Format("\nlst数组的唯一元素：{0}", item));

            Console.ReadKey();
        }
    }
}


using System;
using System.Linq;

namespace DemoSingle2
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] lst = { "乖巧人儿", "霓裳公主", "萧家二小姐", "出云公主" };

            var item = lst.Single(str => str.IndexOf("小姐") > -1);

            try
            {
                var item2 = lst.Single(str => str.IndexOf("公主") > -1);
            }
            catch (Exception e)
            {
                Console.WriteLine(string.Format("应用Single方法出错：{0}", e.Message));
            }

            Console.WriteLine(string.Format("\n数组唯一符合条件的元素：{0}", item));

            Console.ReadKey();
        }
    }
}


4.48 SingleOrDefault

using System;
using System.Linq;

namespace DemoSingleOrDefault1
{
    class Program
    {
        static void Main(string[] args)
        {

            string[] lst = { "乖巧人儿" };
            int[] lst2 = { };
            string[] lst3 = { "出云公主", "乖巧人儿", "萧家二小姐", "霓裳公主" };

            var item = lst.SingleOrDefault();
            var item2 = lst2.SingleOrDefault();

            Console.WriteLine(string.Format("lst数组的第一个元素：{0}", item));
            Console.WriteLine(string.Format("lst2数组的第一个元素：{0}", item2));

            try
            {
                var itme3 = lst3.Single();
            }
            catch (Exception e)
            {
                Console.WriteLine(string.Format("\nlst3应用SingleOrDefault方法出错：{0}", e.Message));
            }


            Console.ReadKey();
        }
    }
}
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace DemoSingleOrDefault2
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] lst = { 10, 20, 30, 40, 50, 100, 50 };

            var item = lst.SingleOrDefault(i => i == 66);

            Console.WriteLine(string.Format("数组的唯一符合条件的元素：{0}", item));

            try
            {

                var item2 = lst.SingleOrDefault(i => i == 50);

            }
            catch (Exception e)
            {
                Console.WriteLine(string.Format("\n应用SingleOrDefault方法出错：{0}", e.Message));
            }



            Console.ReadKey();
        }
    }
}


4.50  ElementAt 获取指定索引处的元素
using System;
using System.Linq;

namespace DemoElementAt
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] lst = { "出云公主", "乖巧人儿", "萧家二小姐", "霓裳公主" };

            var item = lst.ElementAt(2);

            Console.WriteLine(string.Format("索引为2的元素：{0}", item));

            try
            {
                var itme2 = lst.ElementAt(4);
            }
            catch (Exception e)
            {
                Console.WriteLine(string.Format("\n应用ElementAt方法出错：\n{0}", e.Message));
            }

            Console.ReadKey();
        }
    }
}
4.51 ElementAtOrDefault
using System;
using System.Linq;

namespace ElementAtOrDefault
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] lst = { "出云公主", "乖巧人儿", "萧家二小姐", "霓裳公主" };
            int[] lst2 = { 10, 100, 1000, 1000 };

            var item = lst.ElementAtOrDefault(2);
            var itme2 = lst2.ElementAtOrDefault(4);


            Console.WriteLine(string.Format("索引为2的元素：{0}", item));
            Console.WriteLine(string.Format("\n返回lst2的元素默认值：{0}", itme2));

            Console.ReadKey();
        }
    }
}

4.52 检测全部元素是否符合条件
using System;
using System.Linq;

namespace DemoAll
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] lst = { "出云公主", "乖巧人儿", "萧家二小姐", "霓裳公主" };

            bool p = lst.All(s => s.GetTypeCode() == TypeCode.String);
            bool p2 = lst.All(s => s.IndexOf("公主")>-1);

            Console.WriteLine(string.Format("全部元素是否都是String类型：{0}", p));
            Console.WriteLine(string.Format("\n全部元素是否都包含“公主”这个词：{0}", p2));
            Console.ReadKey();
        }
    }
}

4.53  Any 方法

using System;
using System.Linq;

namespace DemoAny1
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] lst = { "出云公主", "乖巧人儿", "萧家二小姐", "霓裳公主" };
            string[] lst2 = {};

            bool p = lst.Any();
            bool p2 = lst2.Any();

            Console.WriteLine(string.Format("lst是否包含元素：{0}", p));
            Console.WriteLine(string.Format("\nlst2是否包含元素：{0}", p2));
            Console.ReadKey();

        }
    }
}

using System;
using System.Linq;

namespace DemoAny2
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] lst = { "出云公主", "乖巧人儿", "萧家二小姐", "霓裳公主" };

            bool p = lst.Any(s => s.IndexOf("公主") > -1);
            bool p2 = lst.Any(s => s.IndexOf("仙子") > -1);

            Console.WriteLine(string.Format("是否有包含“公主”这个词的元素：{0}", p));
            Console.WriteLine(string.Format("\n是否有包含“仙子”这个词的元素：{0}", p2));
            Console.ReadKey();
        }
    }
}
4.56 Contain 检测指定的元素是否存在
using System;
using System.Linq;

namespace DemoContains1
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] lst = { "出云公主", "乖巧人儿", "萧家二小姐", "霓裳公主" };

            bool p = lst.Contains("乖巧人儿");
            bool p2 = lst.Contains("高丽公主");

            Console.WriteLine(string.Format("是否有包含“乖巧人儿”这个元素：{0}", p));
            Console.WriteLine(string.Format("\n是否有包含“高丽公主”这个元素：{0}", p2));
            Console.ReadKey();

        }
    }
}
using System;
using System.Linq;
using DemoDistinct2;

namespace DemoContains2
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] lst = { "出云公主", "乖巧人儿", "萧家二小姐", "霓裳公主", "萧玉霜" };

            bool p = lst.Contains("萧玉霜", new MyEqualityComparer<string>());

            Console.WriteLine(string.Format("是否有包含“萧玉霜”这个元素：{0}", p));
            Console.ReadKey();
        }
    }
}


4.57  Count 方法获取序列元素的数量
using System;
using System.Linq;

namespace DemoCount1
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] lst = { "出云公主", "乖巧人儿", "萧家二小姐", "霓裳公主" };

            try
            {

                int icount = lst.Count();

                Console.WriteLine("序列中元素数量为： {0} ",icount);

            }
            catch (OverflowException)
            {
                Console.WriteLine("序列中元素数量超过Int32类型的最大值。");
            }


            Console.ReadKey();

        }
    }
}

4.58 获取符合自定义条件的元素个数
using System;
using System.Linq;

namespace DemoCount2
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] lst = { "出云公主", "乖巧人儿", "萧家二小姐", "霓裳公主" };

            try
            {

                int icount = lst.Count(str => str.IndexOf("公主") > -1);

                Console.WriteLine("序列中元素数量为： {0} ", icount);

            }
            catch (OverflowException)
            {
                Console.WriteLine("序列中元素数量超过Int32类型的最大值。");
            }


            Console.ReadKey();

        }
    }
}

4.4.18 LongCount 获取一个Int64类型的元素数量
using System;
using System.Linq;

namespace DemoLongCount1
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] lst = { "出云公主", "乖巧人儿", "萧家二小姐", "霓裳公主" };

            long lcount = lst.LongCount();

            Console.WriteLine("序列中元素数量为： {0} ", lcount);

            Console.ReadKey();
        }
    }
}
using System;
using System.Linq;

namespace DemoLongCount2
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] lst = { "出云公主", "乖巧人儿", "萧家二小姐", "霓裳公主" };

            long lcount = lst.LongCount(str => str.IndexOf("公主") > -1);

            Console.WriteLine("序列中元素数量为： {0} ", lcount);

            Console.ReadKey();
        }
    }
}

4.61  Aggregate 将序列元素进行累加

using System;
using System.Linq;

namespace DemoAggregate3
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] lst = { "出云公主", "乖巧人儿", "萧家二小姐", "霓裳公主" };
            int[] ilst = { 10, 20, 30, 40, 50 };

            string str = lst.Aggregate("林晚荣的客户有：", (s1, s2) =>
                                       string.Format("{0}、{1}", s1, s2),
                                       s => s.Remove(s.IndexOf("、"), 1));

            string istr = ilst.Aggregate(50,
                                        (i1, i2) => i1 + i2,
                                        ii => string.Format("累加值：{0}", ii));

            Console.WriteLine(str);
            Console.WriteLine(istr);
            Console.ReadKey();
        }
    }
}


using System;
using System.Linq;
using System.Text.RegularExpressions;

namespace DemoCheckWord
{
    public partial class _Default : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            ///分割敏感词
            string[] wordlst = this.words.Text.Split(new char[]{(char)10,(char)13}, StringSplitOptions.RemoveEmptyEntries);
            ///用户提交的数据
            string utext = this.UserText.Text.Replace("\n","<br>");
            //敏感词掩码
            string wordmask = "*";

            if (this.Page.IsPostBack)
            {
                //生成正则表达式
                string pattern = wordlst.Aggregate("(?is)",
                                                    (w1, w2) => string.Format("{0}|{1}",w1, w2),
                                                    str => str.Remove(str.IndexOf("|"), 1));

                ///找出句子包含的敏感词
                var cw = from w in wordlst
                         where utext.IndexOf(w) > -1
                         select w;

                //包含的敏感词数量
                int icount = cw.Count();

                //合并过滤掉的的敏感词
                string strwd = cw.Aggregate("<b>包含的敏感词：</b>",
                                            (w1, w2) => string.Format("{0}、{1}", w1, w2),
                                            str => str.Remove(str.IndexOf("、"), 1));


                //输出结果
                this.ShowText.Text = string.Format("<b>正则表达式：</b>{0}<br><b>过滤后的内容：</b><br>{1}<br>{2}<br><b>包含的敏感词数量：</b>{3}", pattern, Regex.Replace(utext, pattern, wordmask), strwd, icount);

            }
        }
    }
}