关于datareader，急，分不多，但是虚心请教！

Question

using System;
using System.Collections.Generic;
using System.Text;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;namespace Food.DAL
{
    public static class DBHelper
    {
        private static SqlConnection connection;       
        private static void OpenConnection()
        {
            try
            {
                string connectionString = ConfigurationManager.ConnectionStrings["constring"].ConnectionString;
                if (connection == null)
                {
                    connection = new SqlConnection(connectionString);
                    connection.Open();
                }
                else if (connection.State == System.Data.ConnectionState.Closed)
                {
                    connection.Open();
                }
                else if (connection.State == System.Data.ConnectionState.Broken)
                {
                    connection.Close();
                    connection.Open();
                }
            }
            catch
            {
                throw new ApplicationException("数据库连接失败！");
            }
        }        private static void CloseConnection()
        {
            if (connection != null)
            {
                connection.Close();
            }
        }        public static int ExecuteCommand(string safeSql)
        {
            OpenConnection();
            SqlCommand cmd = new SqlCommand(safeSql, connection);
            int result = cmd.ExecuteNonQuery();
            CloseConnection();
            return result;
        }        public static int ExecuteCommand(string sql, params SqlParameter[] values)
        {
            try
            {
                OpenConnection();
                SqlCommand cmd = new SqlCommand(sql, connection);
                cmd.Parameters.AddRange(values);
                return cmd.ExecuteNonQuery();
            }
            finally
            {
                CloseConnection();
            }
        }        public static int GetScalar(string safeSql)
        {
            try
            {
                OpenConnection();
                SqlCommand cmd = new SqlCommand(safeSql, connection);
                int result = Convert.ToInt32(cmd.ExecuteScalar());
                return result;
            }
            finally
            {
                CloseConnection();
            }
        }        public static int GetScalar(string sql, params SqlParameter[] values)
        {
            try
            {
                OpenConnection();
                SqlCommand cmd = new SqlCommand(sql, connection);
                cmd.Parameters.AddRange(values);
                int result = Convert.ToInt32(cmd.ExecuteScalar());
                return result;
            }
            finally
            {
                CloseConnection();
            }
        }        /// <summary>
        /// 查看新的数量
        /// </summary>
        /// <param name="sql"></param>
        /// <param name="values"></param>
        /// <returns></returns>
        public static object GetScalarWithNewCon(string sql, params SqlParameter[] values)
        {
            using (SqlConnection con = new SqlConnection())
            {
                string connectionString = ConfigurationManager.ConnectionStrings["conString"].ConnectionString;
                con.ConnectionString = connectionString;
                con.Open();
                SqlCommand cmd = new SqlCommand(sql, con);
                cmd.Parameters.AddRange(values);
                return cmd.ExecuteScalar();
            }
        }        public static string GetScalarString(string sql)
        {
            try
            {
                OpenConnection();
                SqlCommand cmd = new SqlCommand(sql, connection);
                string result = cmd.ExecuteScalar().ToString();
                return result;
            }
            finally
            {
                CloseConnection();
            }
        }        public static SqlDataReader GetReader(string safeSql)
        {
            OpenConnection();
            SqlCommand cmd = new SqlCommand(safeSql, connection);
            SqlDataReader reader = cmd.ExecuteReader();
            return reader;
       
        }        public static SqlDataReader GetReader(string sql, params SqlParameter[] values)
        {
            OpenConnection();
            SqlCommand cmd = new SqlCommand(sql, connection);
            cmd.Parameters.AddRange(values);
            SqlDataReader reader = cmd.ExecuteReader();
            return reader;
        }        public static DataTable GetTable(string safeSql)
        {
            try
            {
                OpenConnection();
                DataSet ds = new DataSet();
                SqlCommand cmd = new SqlCommand(safeSql, connection);
                SqlDataAdapter da = new SqlDataAdapter(cmd);
                da.Fill(ds);
                return ds.Tables[0];
            }
            finally
            {
                CloseConnection();
            }
        }
        public static DataTable GetTable(string sql, params SqlParameter[] values)
        {
            try
            {
                OpenConnection();
                DataSet ds = new DataSet();
                SqlCommand cmd = new SqlCommand(sql, connection);
                cmd.Parameters.AddRange(values);
                SqlDataAdapter da = new SqlDataAdapter(cmd);
                da.Fill(ds);
                return ds.Tables[0];
            }
            finally
            {
                CloseConnection();
            }
        }        public static DataSet GetDataSet(string sql)
        {
            try
            {
                OpenConnection();
                DataSet ds = new DataSet();
                SqlCommand cmd = new SqlCommand(sql, connection);
                SqlDataAdapter da = new SqlDataAdapter(cmd);
                da.Fill(ds);
                return ds;
            }
            finally
            {
                CloseConnection();
            }
        }        public static DataSet GetDataSet(string sql, params SqlParameter[] values)
        {
            try
            {
                OpenConnection();
                DataSet ds = new DataSet();
                SqlCommand cmd = new SqlCommand(sql, connection);
                cmd.Parameters.AddRange(values);
                SqlDataAdapter da = new SqlDataAdapter(cmd);
                da.Fill(ds);
                return ds;
            }
            finally
            {
                CloseConnection();
            }
        }
        /// <summary>
        /// 执行存储过程
        /// </summary>
        /// <param name="storedProcName"></param>
        /// <param name="parameters"></param>
        /// <returns></returns>
        public static SqlDataReader RunProcedure(string storedProcName, IDataParameter[] parameters)
        {            string connectionString = ConfigurationManager.ConnectionStrings["conString"].ConnectionString;
            SqlConnection connection = new SqlConnection(connectionString);
            SqlDataReader returnReader;
            connection.Open();
            SqlCommand command = BuildQueryCommand(connection, storedProcName, parameters);
            command.CommandType = CommandType.StoredProcedure;
            returnReader = command.ExecuteReader();
            return returnReader;
        }
        /// <summary>
        /// 执行存储过程
        /// </summary>
        /// <param name="storedProcName"></param>
        /// <param name="parameters"></param>
        /// <returns></returns>
        public static DataTable RunProcedureTable(string storedProcName, IDataParameter[] parameters)
        {
            DataSet dsSet = new DataSet();
            string connectionString = ConfigurationManager.ConnectionStrings["conString"].ConnectionString;
            SqlConnection cnn = new SqlConnection(connectionString);
            SqlDataAdapter sqlDa = new SqlDataAdapter(storedProcName, cnn);
            sqlDa.SelectCommand.CommandType = CommandType.StoredProcedure;
            sqlDa.SelectCommand.Parameters.AddRange(parameters);
            sqlDa.Fill(dsSet);            return dsSet.Tables[0];
        }
        /// <summary>
        /// 为存储过程添加参数
        /// </summary>
        /// <param name="connection"></param>
        /// <param name="storedProcName"></param>
        /// <param name="parameters"></param>
        /// <returns></returns>
        private static SqlCommand BuildQueryCommand(SqlConnection connection, string storedProcName, IDataParameter[] parameters)
        {
            SqlCommand command = new SqlCommand(storedProcName, connection);
            command.CommandType = CommandType.StoredProcedure;
            if (parameters != null)
            {
                foreach (SqlParameter parameter in parameters)
                {
                    command.Parameters.Add(parameter);
                }
            }
            return command;
        }    }
}-------------这是网站dal中的数据库公用类
一个人测试的时候，不会出现异常
发布到网上会出现，n个人浏览时 会出现‘ read关闭时读取无效的异常’我在调用的时候这样写:Dbhelper.GetReader(string safeSql)我想问的是，这个问题跟这个类是静态有关系么？
是不是调用dbhelper的时候，全部用new就行了？
        public static SqlDataReader GetReader(string sql, params SqlParameter[] values)
        {
            OpenConnection();
            SqlCommand cmd = new SqlCommand(sql, connection);
            cmd.Parameters.AddRange(values);
            SqlDataReader reader = cmd.ExecuteReader();            return reader;
        }
这里使用using，出现的错误更多，请大侠们帮忙了
由于页面好多，请有识之士帮小弟这个忙，谢谢了！

Answer 1

你的connection不可以是Static的，否则所有的DB call都共享了一个connection，但是connection的有时候会是关闭的，每一次new一个connection出来。

Answer 2

应该怎么设计啊？是不是用到这个类的时候使用:
dbhelper db=new dahelper();
db.getreader();

Answer 3

对connection不可以是Static的，我也碰到过，方法可以全是静态的