Ajax 在ASP.Net(C#)中即时验证用户名

根据征服ajax一书中的例子改写的,那个例子不能检索数据库,希望对大家有所帮助

--------------------------在web.comfig中添加-----------  
   <httpHandlers>
       <add verb="POST,GET" path="ajaxpro/*.ashx" type="AjaxPro.AjaxHandlerFactory, AjaxPro" />
     </httpHandlers>
----------------------------------------------------------------

-------------------------数据库操作类SqlServerDataBase.cs放在app_code文件夹中---------------
using System;
using System.Data;
using System.Configuration;
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;
namespace mysqlserver
{
     /// <summary>
     /// SqlServerDataBase 的摘要说明
     /// </summary>
     public class SqlServerDataBase
     {
         private string strError = null;
         private int intCount = 0;
         public SqlServerDataBase()
         {
             //
             // TODO: 在此处添加构造函数逻辑
             //
         }
         /// <summary>
         /// 公开方法DBConn,返回数据库连接
         /// </summary>
         /// <returns></returns>
         public SqlConnection DBconn()
         {
             string strConn = "Server=(local);Database=xldf_rhvac_net;Uid=worldpeace;pwd=oneworld&onexldf";
             try
             {
                 return new SqlConnection(strConn);
             }
             catch (Exception)
             {
                 return null;
             }
         }
         /// <summary>
         /// 公开属性ErrorMessage,返回错误信息
         /// </summary>
         public string ErrorMessage
         {
             get
             {
                 return strError;
             }
         }

         /// <summary>
         /// 根据查询语句从数据库检索数据
         /// </summary>
         /// <param name="strSelect">查询语句</param>
         /// <param name="SqlConn">数据库连接</param>
         /// <returns>有数据则返回DataSet对象,否则返回null</returns>
         public DataSet Select(string SelectString, SqlConnection sqlConn)
         {
             strError = "";
             SqlConnection conn;
             if (sqlConn == null)
             {
                 conn = DBconn();
             }
             else
             {
                 conn = sqlConn;
             }
             try
             {
                 //若数据库连接的当前状态是关闭的,则打开连接
                 if (conn.State == ConnectionState.Closed)
                 {
                     conn.Open();
                 }
                 SqlDataAdapter mySqlDataAdapter = new SqlDataAdapter();
                 SqlCommand selectCommand = new SqlCommand(SelectString, conn);
                 selectCommand.CommandType = CommandType.Text;
                 mySqlDataAdapter.SelectCommand = selectCommand;
                 DataSet myDS = new DataSet();
                 mySqlDataAdapter.Fill(myDS);
                 return myDS;
             }
             catch (Exception e)
             {
                 strError = "数据检索失败:" + e.Message;
                 return null;
             }
             finally
             {
                 if (conn.State != ConnectionState.Closed)
                 {
                     conn.Close();
                 }
             }
         }
     }
}
---------------------------------------------------------------------------------------

--------------------------------------前台页面Register.aspx-------------------------------------
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Register.aspx.cs" Inherits="MyRegister.Register" %>

<%@ Register Assembly="Microsoft.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"
     Namespace="Microsoft.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>会员注册</title>
     <LINK href="../stylesheet.css" _fcksavedurl=""../stylesheet.css"" type="text/css" rel="stylesheet">
         <script language="javascript">
         function IsUsernameExist_callback(result)
         {
             var msg = document.getElementById('Message');
             var bun = document.getElementById('Button1');
             var value = result.value;
             if( value == '1' )
             {
                 msg.innerHTML = '用户名未被注册!';
                 msg.style.color='green';
                 bun.disabled=false;
                 return true;            
             }            
             else
             {
                 msg.innerHTML = '用户名已被注册!';
                 msg.style.color='red';   
                 bun.disabled=true;
                 return false;
             }
         }
        
         function VerifyUserName(name)
         {
             MyRegister.Register.GetReturnCode(name, IsUsernameExist_callback);
         }
     </script>
</head>
<body>
     <form id="form1" runat="server">
     <div class="middle" style="height: 1px" >
     <div >
         <asp:Label ID="LbEmail" runat="server" Text="电子邮箱:"></asp:Label>
         <asp:TextBox ID="Email" runat="server"></asp:TextBox><asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" ErrorMessage="*" ControlToValidate="Email"></asp:RequiredFieldValidator>
</div>
     <div >
         <asp:Label ID="LbUserPsw" runat="server" Text="密码:" ></asp:Label>
         <asp:TextBox ID="UserPsw" runat="server" TextMode="Password"></asp:TextBox><asp:RequiredFieldValidator ID="RequiredFieldValidator2" runat="server" ErrorMessage="*" ControlToValidate="UserPsw"></asp:RequiredFieldValidator></div>
     <div >
         <asp:Label ID="LbCheckUserPsw" runat="server" Text="确认密码:" ></asp:Label>
         <asp:TextBox ID="CheckUserPsw" runat="server" TextMode="Password"></asp:TextBox><asp:RequiredFieldValidator ID="RequiredFieldValidator5" runat="server" ErrorMessage="*" ControlToValidate="CheckUserPsw"></asp:RequiredFieldValidator></div>
     <div >
         <asp:Label ID="LbQuestion" runat="server" Text="找回密码问题:"></asp:Label>
         <asp:TextBox ID="Question" runat="server"></asp:TextBox><asp:RequiredFieldValidator ID="RequiredFieldValidator3" runat="server" ErrorMessage="*" ControlToValidate="Question"></asp:RequiredFieldValidator></div>
     <div>
         <asp:Label ID="LbAnswer" runat="server" Text="找回密码答案:"></asp:Label>
         <asp:TextBox ID="Answer" runat="server"></asp:TextBox><asp:RequiredFieldValidator ID="RequiredFieldValidator4" runat="server" ErrorMessage="*" ControlToValidate="Answer"></asp:RequiredFieldValidator></div>
     <div >
         <asp:Label ID="Label1" runat="server" Text="验证码:"></asp:Label>
         <asp:TextBox ID="CheckCode"   runat="server" Width="85px"></asp:TextBox><a href="javascript:loadimage();"><asp:Image id="Image1" runat="server" ImageUrl="Validate.aspx"></asp:Image></a>
        
         <script type="text/javascript" language="JavaScript">
               <!--
                   function loadimage(){
                   document.getElementById("Image1").src = "Validate.aspx?"+Math.random();
                                        }
               //-->  
          </script>
         <asp:RequiredFieldValidator ID="RequiredFieldValidator6" runat="server" ErrorMessage="*" ControlToValidate="CheckCode"></asp:RequiredFieldValidator>
         </div>
     <div>
         <asp:Button ID="Button1" runat="server" Text="确定" OnClick="Button1_Click" /></div>
     <div class="text">
         <asp:Label ID="Message" runat="server" ></asp:Label></div>
     </div>
     </form>
</body>
</html>
--------------------------------------------------------------------------------------------------

------------------------------------后台页面Register.aspx.cs---------------------------
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 mysqlserver;
namespace MyRegister
{
     public partial class Register : System.Web.UI.Page
     {
         protected System.Web.UI.WebControls.TextBox Email1;
         protected void Page_Load(object sender, EventArgs e)
         {
             AjaxPro.Utility.RegisterTypeForAjax(typeof(Register));
             Email.Attributes.Add("OnKeyUp", "VerifyUserName(this.value)");
         }
         [AjaxPro.AjaxMethod]
         public string GetReturnCode(string strName)
         {
             if (!IsUsernameExist(strName))
             {
                 return "1";
             }
             else
             {
                 return "0";
             }
         }
         private bool IsUsernameExist(string strUsername)
         {
             bool bRet = true;
             SqlServerDataBase db = new SqlServerDataBase();
             DataSet ds = db.Select("select * from ypCompanyInfo where CompanyName = '" + strUsername + "'", null);
             if (ds == null || ds.Tables.Count == 0 || ds.Tables[0].Rows.Count == 0)
             {
                 bRet = false;
             }
             else
             {
                 bRet = true;
             }

             return bRet;
         }
         protected void Button1_Click(object sender, EventArgs e)
         {
             string VNum = CheckCode.Text;
             string myEmail = Email.Text.Trim();
             if (VNum != Session["VNum"].ToString() || Session["VNum"].ToString() == null)
             {
                 Message.Text = "验证码错误!";
             }
            
                 else
                 {
                     Response.Redirect("../default.aspx");
                 }
             }

         }
     }
---------------------------------------------------------------------------------

所有的文件都在这了,因为自己也是新手,同时把改写代码过程中遇到的问题说一下
1、类的实例化,也就是如何调用数据库操作类,注意要引用类的命名空间,主要是c#.net的知识。
2、要更改web.config文件,在Page_Load里注册,在使用时加上[AjaxPro.AjaxMethod]。