DataGrid实现增删（带提示）改和分页

或许大家会说，网上已经很多类似文章了，包括孟子的，为什么要再写一次？
我想我们不仅仅要会实现，更多的是需要理解。
下面先帖出代码，再分析一下其中的一些关键代码。
数据库表名:tb1，其中有3个字段，分别是ID自增的主键、vName varchar(50)、iAge int
（以下代码没有做任何错误捕获处理）

前台

<% ... @ Page language = " c# " Codebehind = " WebForm5.aspx.cs " AutoEventWireup = " false " Inherits = " csdn.WebForm5 " %>
<! DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
< HTML >
< HEAD >
< title > WebForm5 </ title >
< meta content ="Microsoft Visual Studio .NET 7.1" name ="GENERATOR" >
< meta content ="C#" name ="CODE_LANGUAGE" >
< meta content ="JavaScript" name ="vs_defaultClientScript" >
< meta content ="http://schemas.microsoft.com/intellisense/ie5" name ="vs_targetSchema" >
</ HEAD >
< body >
< form id ="Form1" method ="post" runat ="server" >
< asp:textbox id ="TextBox1" runat ="server" Width ="88px" ></ asp:textbox >
< asp:TextBox id ="TextBox2" runat ="server" Width ="40px" ></ asp:TextBox >
< asp:Button id ="Button1" runat ="server" Text ="添加" ></ asp:Button >
< asp:datagrid id ="DataGrid1" runat ="server" AutoGenerateColumns ="False" DataKeyField ="ID" AllowPaging ="True"
PageSize ="5" OnEditCommand ="edit" OnCancelCommand ="cancel" OnUpdateCommand ="update" >
< Columns >
< asp:TemplateColumn HeaderText ="姓名" >
< ItemTemplate >
<% ... # DataBinder. Eval (Container.DataItem, " vName " ) %>
</ ItemTemplate >
< EditItemTemplate >
< asp:TextBox id ="name" Runat ="server" Text ='<%# DataBinder.Eval(Container.DataItem,"vName") % > ' Width="88px">
</ asp:TextBox >
</ EditItemTemplate >
</ asp:TemplateColumn >
< asp:TemplateColumn HeaderText ="年龄" >
< ItemTemplate >
<% ... # DataBinder. Eval (Container.DataItem, " iAge " ) %>
</ ItemTemplate >
< EditItemTemplate >
< asp:TextBox id ="age" Runat ="server" Text ='<%# DataBinder.Eval(Container.DataItem,"iAge") % > ' Width="40px">
</ asp:TextBox >
</ EditItemTemplate >
</ asp:TemplateColumn >
< asp:EditCommandColumn UpdateText ="更新" CancelText ="取消" EditText ="编辑" ></ asp:EditCommandColumn >
< asp:ButtonColumn Text ="删除" CommandName ="del" ></ asp:ButtonColumn >
</ Columns >
< PagerStyle Mode ="NumericPages" ></ PagerStyle >
</ asp:datagrid ></ form >
</ body >
</ HTML >

后台

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Data.SqlClient;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
namespace csdn
... {
/**/ /// <summary>
/// WebForm5 的摘要说明。
/// </summary>
public class WebForm5 : System.Web.UI.Page
... {
protected System.Web.UI.WebControls.TextBox TextBox1;
protected System.Web.UI.WebControls.TextBox TextBox2;
protected System.Web.UI.WebControls.Button Button1;
protected System.Web.UI.WebControls.DataGrid DataGrid1;

private void Page_Load( object sender, System.EventArgs e)
... {
// 在此处放置用户代码以初始化页面
if ( ! IsPostBack)
... {
SetBind();
}
}

protected void SetBind()
... {
SqlConnection conn = new SqlConnection(System.Configuration.ConfigurationSettings.AppSettings[ " conn " ]);
SqlDataAdapter da = new SqlDataAdapter( " select * from tb1 " ,conn);
DataSet ds = new DataSet();
da.Fill(ds, " table1 " );
this .DataGrid1.DataSource = ds.Tables[ " table1 " ];
this .DataGrid1.DataBind();
}

Web 窗体设计器生成的代码 #region Web 窗体设计器生成的代码
override protected void OnInit(EventArgs e)
... {
//
// CODEGEN: 该调用是 ASP.NET Web 窗体设计器所必需的。
//
InitializeComponent();
base .OnInit(e);
}

/**/ /// <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 .Button1.Click += new System.EventHandler( this .Button1_Click);
this .DataGrid1.ItemCreated += new System.Web.UI.WebControls.DataGridItemEventHandler( this .DataGrid1_ItemCreated);
this .DataGrid1.ItemCommand += new System.Web.UI.WebControls.DataGridCommandEventHandler( this .DataGrid1_ItemCommand);
this .DataGrid1.PageIndexChanged += new System.Web.UI.WebControls.DataGridPageChangedEventHandler( this .DataGrid1_PageIndexChanged);
this .Load += new System.EventHandler( this .Page_Load);

}
#endregion

private void Button1_Click( object sender, System.EventArgs e)
... {
SqlConnection conn = new SqlConnection(System.Configuration.ConfigurationSettings.AppSettings[ " conn " ]);
SqlCommand comm = new SqlCommand( " insert into tb1 (vName,iAge) values (@vName,@iAge) " ,conn);
SqlParameter parm1 = new SqlParameter( " @vName " ,SqlDbType.NVarChar, 50 );
parm1.Value = this .TextBox1.Text;
SqlParameter parm2 = new SqlParameter( " @iAge " ,SqlDbType.Int);
parm2.Value = this .TextBox2.Text;
comm.Parameters.Add(parm1);
comm.Parameters.Add(parm2);
conn.Open();
comm.ExecuteNonQuery();
conn.Close();
SetBind();
}

private void DataGrid1_ItemCommand( object source, System.Web.UI.WebControls.DataGridCommandEventArgs e)
... {
if (e.CommandName == " del " )
... {
SqlConnection conn = new SqlConnection(System.Configuration.ConfigurationSettings.AppSettings[ " conn " ]);
SqlCommand comm = new SqlCommand( " delete from tb1 where ID=@id " ,conn);
SqlParameter parm1 = new SqlParameter( " @id " ,SqlDbType.Int);
parm1.Value = this .DataGrid1.DataKeys[e.Item.ItemIndex];
comm.Parameters.Add(parm1);
conn.Open();
comm.ExecuteNonQuery();
conn.Close();
SetBind();
}
}

private void DataGrid1_PageIndexChanged( object source, System.Web.UI.WebControls.DataGridPageChangedEventArgs e)
... {
this .DataGrid1.CurrentPageIndex = e.NewPageIndex;
SetBind();
}

protected void edit( object sender,DataGridCommandEventArgs e)
... {
this .DataGrid1.EditItemIndex = e.Item.ItemIndex;
SetBind();
}

protected void cancel( object sender,DataGridCommandEventArgs e)
... {
w

DataGrid实现增删（带提示）改和分页