ASP.NET 在同一個頁面不支持多個 runat=server forms，要解決這個問題，可以把每個 form 放在一個單獨的 panel 控件中，這樣用戶就可以簡單地通過單選按鈕在不同 panel 間切換。
代碼如下：
2FormExample.aspx
<%@ Page language="c#" Codebehind="2FormExample.cs" AutoEventWireup="false"
Inherits="_3leaf_app.C2FormExample" %>
<html><head>
<meta name=vs_targetSchema content="HTML 4.0">
<meta name="GENERATOR" Content="Microsoft Visual Studio 7.0">
<meta name="CODE_LANGUAGE" Content="C#"></head>
<body>
<form method="post" runat="server" ID=Form1>
<p>Lookup by
<asp:RadioButton id=RadioButton1 runat="server" Text="First Name" AutoPostBack="True" groupname=g1
checked=True></asp:RadioButton>
<asp:RadioButton id=RadioButton2 runat="server" Text="Last Name" AutoPostBack="True"
groupname=g1></asp:RadioButton></p>
<p></p>
<p>
<asp:Panel id=Panel1 runat="server" visible=True>
First Name :
<asp:TextBox id=TextBox1 runat="server"></asp:TextBox>
<asp:RequiredFieldValidator id=RequiredFieldValidator1 runat="server" ErrorMessage="*"
ControlToValidate="TextBox1"></asp:RequiredFieldValidator>
<asp:Button id=Button1 runat="server" Text="Submit"></asp:Button>
</asp:Panel>
<asp:Panel id=Panel2 runat="server" visible=False>
Last Name :
<asp:TextBox id=TextBox2 runat="server"></asp:TextBox>
<asp:RequiredFieldValidator id=RequiredFieldValidator2 runat="server" ErrorMessage="*"
ControlToValidate="TextBox2"></asp:RequiredFieldValidator>
<asp:Button id=Button2 runat="server" Text="Submit"></asp:Button>
</asp:Panel>
<p></p>
<p>
<asp:label id=Label1 runat="server"></asp:label>
</p>
</form>
</body></html>
2FormExample.cs
namespace _3leaf_app
{
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;
/// <summary>
/// Summary description for C2FormExample.
/// </summary>
public class C2FormExample : System.Web.UI.Page
{
protected System.Web.UI.WebControls.Button Button2;
protected System.Web.UI.WebControls.RequiredFieldValidator RequiredFieldValidator2;
protected System.Web.UI.WebControls.TextBox TextBox2;
protected System.Web.UI.WebControls.Button Button1;
protected System.Web.UI.WebControls.RequiredFieldValidator RequiredFieldValidator1;
protected System.Web.UI.WebControls.TextBox TextBox1;
protected System.Web.UI.WebControls.Label Label1;
protected System.Web.UI.WebControls.Panel Panel2;
protected System.Web.UI.WebControls.Panel Panel1;
protected System.Web.UI.WebControls.RadioButton RadioButton2;
protected System.Web.UI.WebControls.RadioButton RadioButton1;
public C2FormExample()
{
Page.Init += new System.EventHandler(Page_Init);
}
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
}
}
protected void Page_Init(object sender, EventArgs e)
{
//
// CODEGEN: This call is required by the ASP+ Windows Form Designer.
//
InitializeComponent();
}
/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeComponent()
{
RadioButton1.CheckedChanged += new System.EventHandler (this.RadioButton1_CheckedChanged);
Button1.Click += new System.EventHandler (this.Button1_Click);
RadioButton2.CheckedChanged += new System.EventHandler (this.RadioButton2_CheckedChanged);
Button2.Click += new System.EventHandler (this.Button2_Click);
this.Load += new System.EventHandler (this.Page_Load);
}
public void Button2_Click (object sender, System.EventArgs e)
{
Label1.Text = "You want to search on last name";
}
public void Button1_Click (object sender, System.EventArgs e)
{
Label1.Text = "You want to search on first name";
}
public void RadioButton2_CheckedChanged (object sender, System.EventArgs e)
