超时时间已到。在操作完成之前超时时间已过或服务器未响应。该怎么解决

SqlHelper.csusing System;using System.Collections;using System.Collections.Generic;using System.Text;using System.Data;using System.Data.SqlClient;using System.Configuration;namespace Sxg.WebApp.Data.DBUtility{    public abstract class SqlHelper    {        public static readonly string connectionString = "server=.;database=App;user id=sa;password=abc@abc.com;Max Pool Size = 512;";        private static Hashtable parmCache = Hashtable.Synchronized(new Hashtable());        public static int ExecuteNonQuery(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)        {            SqlCommand cmd = new SqlCommand();            using (SqlConnection conn = new SqlConnection(connectionString))            {                //通过PrePareCommand方法将参数逐个加入到SqlCommand的参数集合中                PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);                int val = cmd.ExecuteNonQuery();                //清空SqlCommand中的参数列表                cmd.Parameters.Clear();                return val;            }        }        public static int ExecuteNonQuery(SqlConnection connection, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)        {            SqlCommand cmd = new SqlCommand();            PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);            int val = cmd.ExecuteNonQuery();            cmd.Parameters.Clear();            return val;        }        public static int ExecuteNonQuery(SqlTransaction trans, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)        {            SqlCommand cmd = new SqlCommand();            PrepareCommand(cmd, trans.Connection, trans, cmdType, cmdText, commandParameters);            int val = cmd.ExecuteNonQuery();            cmd.Parameters.Clear();            return val;        }        public static SqlDataReader ExecuteReader(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)        {            SqlCommand cmd = new SqlCommand();            SqlConnection conn = new SqlConnection(connectionString);            try            {                PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);//PrepareCommand中的第三个参数是事件回滚之类功能用的,想实现可自写一个ExecuteReader的重载                SqlDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);//CommandBehavior.CloseConnection关闭reader关闭连接                cmd.Parameters.Clear();                return rdr;            }            catch            {                conn.Close();                throw;            }        }        public static object ExecuteScalar(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)        {            SqlCommand cmd = new SqlCommand();            using (SqlConnection connection = new SqlConnection(connectionString))            {                PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);                object val = cmd.ExecuteScalar();                cmd.Parameters.Clear();                return val;            }        }        public static object ExecuteScalar(SqlConnection connection, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters)        {            SqlCommand cmd = new SqlCommand();            PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);            object val = cmd.ExecuteScalar();            cmd.Parameters.Clear();            return val;        }        public static void CacheParameters(string cacheKey, params SqlParameter[] commandParameters)        {            parmCache[cacheKey] = commandParameters;        }        public static SqlParameter[] GetCachedParameters(string cacheKey)        {            SqlParameter[] cachedParms = (SqlParameter[])parmCache[cacheKey];            if (cachedParms == null)                return null;            //新建一个参数的克隆列表            SqlParameter[] clonedParms = new SqlParameter[cachedParms.Length];            //通过循环为克隆参数列表赋值            for (int i = 0, j = cachedParms.Length; i < j; i++)                //使用clone方法复制参数列表中的参数                clonedParms[i] = (SqlParameter)((ICloneable)cachedParms[i]).Clone();            return clonedParms;        }        private static void PrepareCommand(SqlCommand cmd, SqlConnection conn, SqlTransaction trans, CommandType cmdType, string cmdText, SqlParameter[] cmdParms)        {            //判断数据库连接状态            if (conn.State != ConnectionState.Open)                conn.Open();            cmd.Connection = conn;            cmd.CommandText = cmdText;            //判断是否需要事物处理            if (trans != null)                cmd.Transaction = trans;            cmd.CommandType = cmdType;            if (cmdParms != null)            {                foreach (SqlParameter parm in cmdParms)                    cmd.Parameters.Add(parm);            }        }    }}