【求助】asp.net写了一个登陆窗口，自己找不出问题

其中我的SqlServer.cs类中的代码是：
C# code:

using System;
using System.Data;
using System.Configuration;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Data.SqlClient;
/// <summary>
///SqlServer 的摘要说明
/// </summary>
public class SqlServer
{
public SqlServer()
{
//
//TODO: 在此处添加构造函数逻辑
//
}


public string Login(string a,string b)
{
SqlConnection conn = new SqlConnection();
conn.ConnectionString = "server=245F77242BAE43A;uid=sa;pwd=sa;database=Login";
string JJ = a, BB = b;
try
{
conn.Open();
SqlCommand cmd = new SqlCommand("select count(*) from user where UserId=" + JJ + " and Password=" + BB + "", conn);
int count = Convert.ToInt32(cmd.ExecuteScalar());

string result;


if (count > 0)
{
result = "登录成功";
return result;
}
else
{
result = "密码错误";
return result;