以下这段代码：
protected System.Web.UI.WebControls.Button btnCreate;
protected System.Web.UI.WebControls.Table tb;
protected static int i = 0;private void btnCreate_Click(object sender, System.EventArgs e)
{
i = i + 1;
TableRow r = new TableRow ();
TableCell c1 = new TableCell ();
TableCell c2 = new TableCell ();
TableCell c3 = new TableCell ();
TextBox t1 = new TextBox();
TextBox t2 = new TextBox();
DropDownList l = new DropDownList ();
t1.ID = "tbx1"+ i;
t2.ID = "tbx2"+ i;
l.ID = "ddl"+ i; c1.Controls.Add (t1);
c2.Controls.Add (t2);
c3.Controls.Add (l);
r.Cells.Add (c3);
r.Cells.Add (c1);
r.Cells.Add (c2);
tb.Rows.Add (r);
}
本意是想按下btnCreate按钮后，就在页面的table控件内创建一个下拉框和两个文本框，运行后，第一次按下按钮，是创建出了这三个控件，但是再按下就没有用了~~~~~可能是什么原因啊？：（
protected System.Web.UI.WebControls.Button btnCreate;
protected System.Web.UI.WebControls.Table tb;
protected static int i = 0;private void btnCreate_Click(object sender, System.EventArgs e)
{
i = i + 1;
TableRow r = new TableRow ();
TableCell c1 = new TableCell ();
TableCell c2 = new TableCell ();
TableCell c3 = new TableCell ();
TextBox t1 = new TextBox();
TextBox t2 = new TextBox();
DropDownList l = new DropDownList ();
t1.ID = "tbx1"+ i;
t2.ID = "tbx2"+ i;
l.ID = "ddl"+ i; c1.Controls.Add (t1);
c2.Controls.Add (t2);
c3.Controls.Add (l);
r.Cells.Add (c3);
r.Cells.Add (c1);
r.Cells.Add (c2);
tb.Rows.Add (r);
}
本意是想按下btnCreate按钮后，就在页面的table控件内创建一个下拉框和两个文本框，运行后，第一次按下按钮，是创建出了这三个控件，但是再按下就没有用了~~~~~可能是什么原因啊？：（
<%@ Page language="c#" Codebehind="动态添加控件（一）.aspx.cs" AutoEventWireup="false" Inherits="bsTest2005_8_16.Samples.动态添加控件_一_" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
<HTML>
<HEAD>
<title>动态添加控件（一）</title>
<meta name="GENERATOR" Content="Microsoft Visual Studio .NET 7.1">
<meta name="CODE_LANGUAGE" Content="C#">
<meta name="vs_defaultClientScript" content="JavaScript">
<meta name="vs_targetSchema" content="http://schemas.microsoft.com/intellisense/ie5">
</HEAD>
<body MS_POSITIONING="GridLayout">
<form id="Form1" method="post" runat="server">
<FONT face="宋体">
<asp:Button id="Button1" style="Z-INDEX: 101; LEFT: 536px; POSITION: absolute; TOP: 312px" runat="server"
Text="增加一个TextBox"></asp:Button>
<asp:Button id="Button2" style="Z-INDEX: 102; LEFT: 512px; POSITION: absolute; TOP: 344px" runat="server"
Text="提取第一个TextBox的值"></asp:Button>
<asp:TextBox id="txt" style="Z-INDEX: 103; LEFT: 528px; POSITION: absolute; TOP: 376px" runat="server"></asp:TextBox></FONT>
</form>
</body>
</HTML>
****************************************
using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
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 bsTest2005_8_16.Samples
{
/// <summary>
/// 动态添加控件_一_ 的摘要说明。
/// </summary>
public class 动态添加控件_一_ : System.Web.UI.Page
{
protected System.Web.UI.WebControls.Button Button2;
protected System.Web.UI.WebControls.TextBox txt;
protected System.Web.UI.WebControls.Button Button1;
private ArrayList TextBoxsList
{
get
{
if(ViewState["myTextBoxsList"]==null)
return new ArrayList();
else
return ViewState["myTextBoxsList"] as ArrayList;
}
set
{
ViewState["myTextBoxsList"] = value;
}
}
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(Page.IsPostBack)
{
for(int i=0;i<this.TextBoxsList.Count;i++)
{
string txtID = this.TextBoxsList[i].ToString();
TextBox tmp = new TextBox();
tmp.ID = txtID;
Page.Controls[1].Controls.Add(tmp);
tmp.Text = Request.Form[txtID].ToString();
}
}
} private void Button1_Click(object sender, System.EventArgs e)
{
TextBox tmp = new TextBox();
tmp.ID = "TextBox" + this.TextBoxsList.Count.ToString();
Page.Controls[1].Controls.Add(tmp); ArrayList array = this.TextBoxsList;
array.Add(tmp.ID);
this.TextBoxsList = array;
} private void Button2_Click(object sender, System.EventArgs e)
{
this.txt.Text = ((TextBox)Page.FindControl("TextBox1")).Text;
} #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.Button2.Click += new System.EventHandler(this.Button2_Click);
this.Load += new System.EventHandler(this.Page_Load); }
#endregion
}
}