C#三层架构

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;

namespace DataAccess
{
    class SQLHelper
    {
        private SqlConnection conn = new SqlConnection("data source=.;initial catalog=student;integrated security=sspi");//需要添加引用
        /// <summary>
        /// 执行存储过程返回DataSet
        /// </summary>
        /// <param name="procName">存储过程名称</param>
        /// <param name="prams">参数列表</param>
        /// <returns>DataSet</returns>
        public DataSet ExecuteDataSet(string procName, SqlParameter[] prams)
        {
            DataSet ds = new DataSet();

            SqlCommand command = new SqlCommand(procName, conn);
            command.CommandType = CommandType.StoredProcedure;

            if (prams != null)
            {
                foreach (SqlParameter parameter in prams)
                    command.Parameters.Add(parameter);

            }

            SqlDataAdapter da = new SqlDataAdapter(command);
            da.Fill(ds);
            command.Parameters.Clear();
            return ds;
        }

        /// <summary>
        /// 执行存储过程返回DataTable
        /// </summary>
        /// <param name="procName">存储过程名称</param>
        /// <param name="prams">参数列表</param>
        /// <returns>DataTable</returns>
        public DataTable ExecuteDataTable(string procName, SqlParameter[] prams)
        {
            DataTable dt = new DataTable();

            SqlCommand command = new SqlCommand(procName, conn);
            command.CommandType = CommandType.StoredProcedure;

            if (prams != null)
            {
                foreach (SqlParameter parameter in prams)
                    command.Parameters.Add(parameter);
            }

            SqlDataAdapter da = new SqlDataAdapter(command);
            da.Fill(dt);
            command.Parameters.Clear();