书的增删改查

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

namespace Librarys
{
    public partial class Homepage : Form
    {
        public Homepage()
        {
            InitializeComponent();
        }
        DataSet ds = new DataSet();//连接数据集
        private void Homepage_Load(object sender, EventArgs e)
        {
            //主窗体
            Show(); //调用所有书的方法
        }
        #region 显示所有树书名
        public void Show()
        {
            SqlConnection con = new SqlConnection(Tools.str);//创建 Connection对象
            //SQL语句
            string sql = "select * from Homepage";
            //创建DataAdapter数据适配器
            SqlDataAdapter da = new SqlDataAdapter(sql, con);
            //填充数据
            da.Fill(ds, "Homepage");
            //数据源
            dvgList.DataSource = ds.Tables["Homepage"];
        }
            #endregion
        private void btnInquiry_Click(object sender, EventArgs e)
        {
            #region 按类型查询书
            DataView dv = new DataView(ds.Tables ["Homepage"]);
            if (!(txtBookName.Text.Trim().Equals (""))&&(txtAuthor.Text.Trim ().Equals("")))
            {
                dv.RowFilter = "BookName like'%"+txtBookName.Text+"%'";
                dvgList.DataSource = dv;
            }else if ((txtBookName.Text .Trim ().Equals (""))&&(!txtAuthor.Text .Trim ().Equals ("")))
            {
                dv.RowFilter ="Author like'%"+txtAuthor.Text+"%'";
                dvgList.DataSource=dv;
            }
            else if (!(txtBookName.Text.Trim().Equals (""))&&(!txtAuthor.Text .Trim ().Equals ("")))
            {
                dv.RowFilter = "BookName like'%"+txtBookName.Text+"%'and Author like '%"+txtAuthor.Text+"%'";
            }
            dvgList.DataSource = dv;
            #endregion
        }

        private void btnAdd_Click(object sender, EventArgs e)
        {
            #region 跳转新增页面
            FrmMain frm = new FrmMain();
            frm.stu = this;
            frm.Show();
            #endregion
        }
        #region 刷新页面
        public void input()
        {
            if (ds.Tables !=null)
            {
                ds.Tables["Homepage"].Clear();
            }
            Show();
        }
        #endregion
        private void 修改ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            #region 修改页面
            FrmMain frm = new FrmMain();
            frm.Text = "修改";
            if (dvgList.SelectedRows[0]!=null)
            {
                string name = dvgList.SelectedRows[0].Cells["BookName"].Value.ToString();
                frm.BookName = name;
            }
            frm.stu = this;
            frm.Show();
            
            #endregion
        }

        private void 删除ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            #region 删除页面
            if (dvgList .SelectedRows [0]!=null)
            {
                string name = dvgList.SelectedRows[0].Cells["BookName"].Value.ToString();
                SqlConnection con = new SqlConnection(Tools .str);
                string sql = "Delete from Homepage where BookName='"+name+"'";
                SqlCommand cmd = new SqlCommand(sql, con);
                try
                {
                    con.Open();
                    int result = Convert.ToInt32(cmd.ExecuteScalar());
                    if (result > 0)
                    {
                        MessageBox.Show("删除成功!");
                    }
                    else if (result ==0)
                    {
                        MessageBox.Show ("未选中行!请重新选择");
                    }
                    else
                    {
                        MessageBox.Show("删除失败!");
                    }
                   

                }
                catch (Exception)
                {
                    MessageBox.Show("网络连接异常!");
                    throw;
                }
                finally
                {
                    con.Close();
                }
                input();
            }
            
            #endregion
        }
        
    }
}

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

namespace Librarys
{
    public partial class FrmMain : Form
    {
        public FrmMain()
        {
            InitializeComponent();
        }
        public Homepage stu;
        public string BookName;
        private void FrmMain_Load(object sender, EventArgs e)
        {
            txtBookName.Text = BookName;
        }
        SqlConnection con = new SqlConnection(Tools .str );
        private void btnConservation_Click(object sender, EventArgs e)
        {
            #region 保存按钮
            if (this.Text .Trim().Equals ("新增"))
            {
                insert();
            }
            else if(this.Text .Trim ().Equals ("修改"))
            {
                update();
            }
            #endregion
        }
        #region 新增的方法
        public void insert()
        {
            con.Open();
            string sql = "insert into Homepage values('"+txtBookName.Text +"','"+txtAuthor.Text +"','"+txtPrice.Text +"','"+txtQuantity.Text +"')";
            SqlCommand cmd = new SqlCommand(sql, con);
            try
            {
                int retult = Convert.ToInt32(cmd.ExecuteScalar());
                if (retult >= 0)
                {
                    MessageBox.Show("新增成功!");
                }
                else
                {
                    MessageBox.Show("新增失败!");
                }

            }
            catch (Exception)
            {
                MessageBox.Show("网络连接异常!");
                throw;
            }
            finally
            {
                con.Close();
            }
            stu.input();

        } 
        #endregion
        #region 修改的方法
        public void update()
        {
            con.Open();
            string sql = @"update Homepage set BookName='"+txtBookName.Text+"',Author='"+txtAuthor.Text +"',Price='"+txtPrice.Text+"',Quantity='"+txtQuantity.Text+"'";
            SqlCommand cmd = new SqlCommand(sql, con);
            try
            {
                int retult = Convert.ToInt32(cmd.ExecuteScalar());
                if (retult >= 0)
                {
                    MessageBox.Show("修改成功!");
                }
                else
                {
                    MessageBox.Show("修改失败!");
                }

            }
            catch (Exception)
            {
                MessageBox.Show("网络连接异常!");
                throw;
            }
            finally
            {
                con.Close();
            }
            stu.input();
        }

        #endregion
    }
}