简单的用户注册实例，包括两个Panel，一个是用户注册输入界面，一个是注册成功界面。
一个label，用户给出用户名已经存在的提示。
输入控件有用户名，密码，密码确认和电子邮件，共4个TextBox。
验证控件包括：
RequireFieldValidator:验证用户输入是否为空。此处验证用户名和密码。使用ControlToValidate属性设置绑定到需要验证的控件。
RegularExpressionValidator:验证用户输入是否符合格式。此处用于验证电子邮件
CompareValidator:验证用户两次输入是否一致。此次用于验证密码。使用ControlToCompare属性设置相比较的控件，ControlToValidate绑定到需要验证的控件。
页面代码：
register<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>新用户注册</title>
</head>
<body>
<form id="form1" runat="server" >
<div align="center">
<asp:panel ID="Panel1" runat="server" Width="500px">
<table align="center">
<tr align="center">
<td colspan="3">用户注册（*为必填项）</td>
</tr>
<tr align="left">
<td style=" 98px">用户名：</td>
<td style=" 5px">
<asp:TextBox ID="TxtUser" runat="server"></asp:TextBox></td>
<td style=" 234px">
<asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" ErrorMessage="* 用户名不能为空" ControlToValidate="TxtUser"></asp:RequiredFieldValidator>
<asp:Label ID="Label1" runat="server" Text="用户名已经存在，请换一个" Visible="false"></asp:Label></td>
</tr>
<tr align="left">
<td style=" 98px">密码：</td>
<td style=" 5px">
<asp:TextBox ID="TxtPwd1" runat="server"></asp:TextBox></td>
<td style=" 234px">
<asp:RequiredFieldValidator ID="RequiredFieldValidator2" runat="server" ErrorMessage="* 密码不能为空" ControlToValidate="TxtPwd1"></asp:RequiredFieldValidator></td>
</tr>
<tr align="left">
<td style=" 98px">密码确认：</td>
<td style=" 5px">
<asp:TextBox ID="TxtPwd2" runat="server"></asp:TextBox></td>
<td style=" 234px">
<asp:CompareValidator ID="CompareValidator1" runat="server" ErrorMessage="* 两次输入不一样" ControlToCompare="TxtPwd1" ControlToValidate="TxtPwd2"></asp:CompareValidator></td>
</tr>
<tr align="left">
<td style=" 98px">电子邮件：</td>
<td style=" 5px">
<asp:TextBox ID="TxtEmail" runat="server"></asp:TextBox></td>
<td style=" 234px">
<asp:RegularExpressionValidator ID="RegularExpressionValidator1" runat="server" ErrorMessage="电子邮件格式不正确" ControlToValidate="TxtEmail" ValidationExpression="\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*"></asp:RegularExpressionValidator></td>
</tr>
<tr>
<td colspan="3">
<asp:Button ID="Button1" runat="server" Text="确定" OnClick="Button1_Click" />
</td>
</tr>
</table>
</asp:panel>
<asp:panel ID="Panel2" runat="server" Width="500px">
<br />
<table>
<tr>
<td>注册成功，感谢您的使用！</td>
</tr>
<tr>
<td><a href="Default.aspx">>>返回</a></td>
</tr>
</table>
</asp:panel>
</div>
</form>
</body>
</html>
处理代码：
registerusing System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;
public partial class register : System.Web.UI.Page
{
private static string connString=@"Server=localhost;Integrated Security=True; Database=Test";
protected void Page_Load(object sender, EventArgs e)
{
Panel1.Visible = true;
Panel2.Visible = false;
Label1.Visible = false;
}
protected void Button1_Click(object sender, EventArgs e)
{
if (Page.IsValid)
{
if (UserValid())
{
SqlConnection con = new SqlConnection(connString);
string strSql = "insert into tb_user(UserName,Password,Email) values('" + TxtUser.Text.Trim() + "','" + TxtPwd1.Text.Trim() + "','" + TxtEmail.Text.Trim() + "')";
SqlCommand cmd = new SqlCommand(strSql, con);
try
{
con.Open();
cmd.ExecuteNonQuery();
}
catch
{ }
finally
{
cmd.Dispose();
con.Close();
}
Panel1.Visible = false;
Panel2.Visible = true;
}
else
{
Label1.Visible = true;
}
}
}
/// <summary>
/// 验证用户名是否存在
/// </summary>
/// <returns></returns>
private bool UserValid()
{
SqlConnection con = new SqlConnection(connString);
string strSql = "select * from tb_user where UserName='" + TxtUser.Text.Trim() + "'";
try
{
con.Open();
SqlCommand cmd = new SqlCommand(strSql, con);
SqlDataReader dr = cmd.ExecuteReader();
if (dr.Read())
{
return false;
}
else
{
return true;
}
}
catch
{
return true;
}
finally
{
con.Close();
}
}
}