下面是CheckUserName.htm页面的代码
1 < html xmlns = " http://www.w3.org/1999/xhtml " > 2 < head > 3 < title > 无标题页 < / title> 4 < script src = " http://www.cnblogs.com/../JQuery/js/jquery-1.4.2.js " type = " text/javascript " >< / script> 5 < script type = " text/javascript " > 6 $( function (){ 7 $( " #textUserName " ).blur( function (){ // 鼠标离开文本框时触发 8 var username = $( " #textUserName " ).val(); 9 // 向CheckUserName发出请求，参数username，返回的数据用function(data,satus){}处理 10 $.post( " CheckUserName.ashx " ,{ " username " :username}, function (data,status){ 11 if (status == " success " ){ 12 alert(data); 13 } 14 }); 15 }) 16 }); 17 < / script> 18 < / head> 19 < body > 20 < input type = " text " id = " textUserName " / > 21 < / body> 22 < / html>
下面的是CheckUserName.ashx页面的内容。
1 using System; 2 using System.Web; 3 using System.Data.SqlClient; 4 using System.Configuration; 5 6 public class CheckUserName : IHttpHandler { 7 8 public void ProcessRequest (HttpContext context) { 9 context.Response.ContentType = " text/plain " ; 10 string username = context.Request[ " username " ]; 11 string connection = ConfigurationManager.ConnectionStrings[ " TestDBConnectionString " ].ConnectionString; 12 using (SqlConnection sqlconn = new SqlConnection(connection)) 13 { 14 using (SqlCommand sqlcommand = new SqlCommand()) 15 { 16 sqlcommand.Connection = sqlconn; 17 sqlcommand.CommandText = " select * from UserNameLoginCheck where LoginUserName = @username " ; 18 sqlcommand.Parameters.AddWithValue( " @username " , username); 19 int SelectCount; 20 try 21 { 22 sqlconn.Open(); 23 using (SqlDataReader sqldatareader = sqlcommand.ExecuteReader()) 24 { 25 // 如果有找到，sqldatareader.Read()执行结果为true,否则为false. 26 while (sqldatareader.Read()) 27 { 28 context.Response.Write( " 用户名已存在，请重新选择 " ); return ; 29 } 30 context.Response.Write( " 用户名可用 " ); return ; 31 } 32 } 33 catch (Exception ee) 34 { 35 throw ee; 36 } 37 finally 38 { 39 sqlconn.Close(); 40 sqlconn.Dispose(); 41 sqlcommand.Dispose();
//这个地方感觉有点多余，因为后面出了using的范围系统会自动注销sqlconn和sqlcommand，不知道大家怎么看呢？ 42 } 43 } 44 } 45 } 46 47 public bool IsReusable { 48 get { 49 return false ; 50 } 51 } 52 53 }
欢迎大家批评指正！