[网络收集]AJAX 验证用户名是否存在，使用UpdatePanel

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Index.aspx.cs" Inherits="Index" %>

 

 

<% @ Register Assembly = " System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken

=31bf3856ad364e35" Namespace="System.Web.UI" TagPrefix="asp" %>

 

 

<! DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" >

 

 

< html  xmlns ="http://www.w3.org/1999/xhtml"   >
< head  runat ="server" >
     < title > 验证用户名是否存在 </ title >
</ head >
< body >
     < form  id ="form1"  runat ="server" >
     < div >
         < asp:ScriptManager  ID ="ScriptManager1"  runat ="server" >
         </ asp:ScriptManager >
    
     </ div >
         < asp:UpdatePanel  ID ="UpdatePanel1"  runat ="server" >
             < ContentTemplate >
                 < asp:TextBox  ID ="tb_username"  runat ="server"  Width ="85px"  AutoPostBack ="True"

 OnTextChanged="tb_username_TextChanged"></asp:TextBox>
                <asp:Label ID="lb_info" runat="server" Width="76px"></asp:Label>
                <asp:TextBox ID="tb_Pwd" runat="server" Width="85px" TextMode="Password"></asp:TextBox><br />
                &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;
                <asp:Button ID="Button1" runat="server" Text="注册" OnClick="Button1_Click" />
            </ContentTemplate>
        </asp:UpdatePanel>
    </form>
</body>
</html>

 

using 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  Index : System.Web.UI.Page
{
     protected   void  Page_Load( object  sender, EventArgs e)
    {
         if  ( ! this .IsPostBack)
        {
            ScriptManager1.SetFocus( " tb_username " );
        }
    }
     private   bool  CheckUser()
    {
         int  count  =   0 ;
        SqlConnection conn  =   new  SqlConnection( " server=.;uid=sa;pwd='';database=UserInfo " );
         string  username  =   this .tb_username.Text;
         string  strsql  =   " select count(uid) from userinfo where username=' " + username + " ' " ;
        SqlCommand cmd  =   new  SqlCommand(strsql,conn);
        conn.Open();
        count  =  ( int )cmd.ExecuteScalar();
        conn.Close();
         if  (count  ==   0 )
        {
             return   true ;
        }
         else
        {
             return   false ;
        }

 

    }

 

protected   void  Button1_Click( object  sender, EventArgs e)
    {
         if  ( ! CheckUser())
        {
             this .lb_info.Text  =   " 用户名已经存在 " ;
            ScriptManager.RegisterStartupScript( this .UpdatePanel1, UpdatePanel1.GetType(),  "" ,

 "document.getElementById('tb_username').select();", true);
        }

 

摘自http://www.cnblogs.com/lavenderzh/archive/2009/05/23/1487588.html