数据层代码如下：

using System;

using System.Data;

using System.Data.SqlClient;

using System.Configuration;

namespace AspnetPaging

{

     public class DataAccess

     {

         private static string connString = ConfigurationSettings.AppSettings["ConnString"];

         private DataAccess()

         {

          }

         public static DataSet GetCustomersData()

         {

              SqlConnection conn = new SqlConnection(connString);

              SqlCommand comm = new SqlCommand("GetCustomers",conn);

              comm.CommandType = CommandType.StoredProcedure;

              SqlDataAdapter dataAdapter = new SqlDataAdapter(comm);

              DataSet ds = new DataSet();

              dataAdapter.Fill(ds);

              return ds;

         }

     }

}