C#基础学习之线程【新手学习 欢迎指正】

线程是程序中顺序执行的流程，一个进程可以由多个线程组成，给个线程都可能单独执行

• 创建线程和停止线程

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

namespace threadproj
{
    class Program
    {
        static void Main(string[] args)
        {
            //Thread类创建并控制线程，该类的构造函数接受ThreadStart委托，该委托包装希望作为单独线程运行的函数

　　　　Thread t = new Thread(new ThreadStart( Dosomething));
            t.Start();//启动线程
            Console.WriteLine("continue with the execution...");//主线程执行的输出
            while (!t.IsAlive) ;
            Thread.Sleep(1);//目的可以为Dosomething（）函数提供执行的机会
            t.Abort();//停止线程
            Console.ReadLine();
        }
        static void Dosomething()
        {

            try
            {
                while (true)
                {
                    Console.WriteLine("Doing something...");
                }
            }
            catch (ThreadAbortException ex)
            {
               
                Console.WriteLine(ex.Message);
            }
        }
    }
}

可以向线程传递形参

一是在类中包装函数，并且通过特性传入形参

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

namespace threadproj
{
    class Program
    {
        static void Main(string[] args)
        {
            Someclass sc = new Someclass();
            sc.msg = "helloworld";
            Thread t = new Thread( new ThreadStart( sc.Dosomething));
            t.Start();
           
            Console.ReadLine();
        }

        class Someclass
        {
            public string msg { get; set; }

            public static void Dosomething()
            {

                try
                {
                    while (true)
                    {
                        Console.WriteLine("Doing something...{0}",msg);
                    }
                }
                catch (ThreadAbortException ex)
                {

                    Console.WriteLine(ex.Message);
                }
            }
        }
    }
}

二是使用ParameterizedThreadStart委托而非ThreadStart委托

public static void Dosomething()
            {

                try
                {
                    while (true)
                    {
                        Console.WriteLine("Doing something...{0}",msg);
                    }
                }
                catch (ThreadAbortException ex)
                {

                    Console.WriteLine(ex.Message);
                }
            }
   static void Main(string[] args)
        {
             Thread t = new Thread( new ParameterizedThreadStart( Dosomething));
            t.Start("helloworld");//用start（）方法传递实参
            
            Console.ReadLine();
        }     

 

• 线程同步问题

       1.使用Interlocked类 主要用于多个线程共享的变量执行原子操作

        2.lock关键字

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

namespace threadproj
{
    class Program
    {
        static int num = 500;
        static object obj = new object();

        static void Main(string[] args)
        {
            Thread t1 = new Thread(new ThreadStart(Debit));
            t1.Start();
            Thread t2 = new Thread( new ThreadStart( Credit));
           t2.Start();
           
            Console.ReadLine();
        }

       

             static void Credit()
             {

                for (int i = 0; i < 15;i++ )
                {
                    lock(obj)
                    {
                        num += 100;
                        Console.WriteLine("After credit ,num is " + num);
                    }
                   
                }
               
            
               
            }
             static void Debit()
             {

                 for (int i = 0; i < 10; i++)
                 {

                     lock (obj)
                     {
                         num -= 100;
                         Console.WriteLine("After dedit ,num is " + num);
                     }
                 }

               

             }
       
    }
}

3.Monitor类

 　　　　　　lock (obj)
                     {
                         num -= 100;
                         Console.WriteLine("After dedit ,num is " + num);
                     }

等价于Monitor.Enter(obj);

　　　　num -= 100;
           Console.WriteLine("After dedit ,num is " + num);

　　　　Monitor.Exit(obj);

 

　　

• Winform 中BackgroundWorker组件的应用

添加控件如下描述

private System.ComponentModel.BackgroundWorker backgroundWorker1;
        private System.Windows.Forms.Label label1;
        private System.Windows.Forms.TextBox txtNum;
        private System.Windows.Forms.Label lb1Result;
        private System.Windows.Forms.Button btnCancel;
        private System.Windows.Forms.Button btnStart;
        private System.Windows.Forms.Label label3;
        private System.Windows.Forms.ProgressBar progressBar1;

 

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

 

namespace backgroundworkerproj
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

 

        private void btnStart_Click(object sender, EventArgs e)
        {
            lb1Result.Text = string.Empty;//显示结果的标签清空
            btnCancel.Enabled = true;
            btnStart.Enabled = false;
            progressBar1.Value = 0;//进度条初始为0
            backgroundWorker1.RunWorkerAsync(txtNum.Text);//开始执行后台操作
        }

 

        private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
        {
            BackgroundWorker worker = (BackgroundWorker)sender;//在单线程上执行操作
            e.Result = sunnumbers(double.Parse(e.Argument.ToString()), worker, e);//获取异步操作结果的值
        }

 

       //求和函数 返回sum

　　 private double sunnumbers(double number,BackgroundWorker worker,DoWorkEventArgs e)
        {
            int lastpercent = 0;
            double sum = 0;
            for (double i = 0; i <= number;i++ )
            {
                if (worker.CancellationPending)//指示应用程序是否已经请求取消后台操作 返回bool值
                {
                    e.Cancel = true;
                }
                else
                {
                    sum += i;
                    if(i%10==0)
                    {
                        int percentdone = (int)((i / number) * 100);
                        if (percentdone>lastpercent)
                        {
                            worker.ReportProgress(percentdone);
                            lastpercent = percentdone;
                        }
                    }
                }
            }
            return sum;
        }

 

        private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
        {
            progressBar1.Value = e.ProgressPercentage;
            lb1Result.Text = e.ProgressPercentage.ToString() + "%";
        }

 

        private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            if (e.Error!=null)
            {
                MessageBox.Show(e.Error.Message);
            }
            else if(e.Cancelled)
                MessageBox.Show("canceled");
            else
            {
                lb1Result.Text = "Sum of 1 to  "+txtNum.Text +"is "+e.Result;
            }
            btnStart.Enabled = true;
            btnCancel.Enabled = false;
        }

 

        private void btnCancel_Click(object sender, EventArgs e)
        {
            backgroundWorker1.CancelAsync();
            btnCancel.Enabled = false;
        }
    }
}