自定义验证控件两层

第一层；
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;

namespace WebApplication3
{
    public partial class _Default : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {

        }

        protected void CustomValidator1_ServerValidate(object source, ServerValidateEventArgs args)
        {
            //string connstr = ConfigurationManager.AppSettings["zd"];
            //SqlConnection con = new SqlConnection(connstr);
            //con.Open();
            //SqlCommand cmd=new SqlCommand("select count(*) from 学生表 where stuName='"+this.TextBox1.Text+"'",con);
            //int name = Convert.ToInt32(cmd.ExecuteScalar());
            string con = ConfigurationManager.AppSettings["zd"];
            string sqlcmd="select count(*) from 学生表 where stuName='"+this.TextBox1.Text+"'";
            int name = DAL.database.ReturnName(con, sqlcmd);

            if (name > 0)
            {
                args.IsValid = false;
            }
            else
            {
                args.IsValid = true;
            }
        }
    }
}



DAL层:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.Data.SqlClient;



namespace DAL
{
    public class database
    {
        public static int ReturnName(string constr, string sqlcmdsql)
        {
            SqlConnection cn = new SqlConnection(constr);
            cn.Open();
            SqlCommand cmd = new SqlCommand(sqlcmdsql,cn);
            int name = Convert.ToInt32(cmd.ExecuteScalar());
            return name;
        }
    }
}