当你使用LINQ做底层时，最好设计一个工厂，不要把LINQ的动作暴露给业务层

 1: using System;

  2: using System.Collections.Generic;

  3: using System.Linq;

  4: using System.Text;

  5: using System.Data.Linq;

  6: using System.Threading;

  7:

  8: namespace Data

  9: {

 10:     /// <summary>

 11:     /// LINQ数据库连接对象制造工厂

 12:     /// </summary>

 13:     static internal class DataContextFactory

 14:     {

 15:

 16:         static System.Timers.Timer sysTimer = new System.Timers.Timer(10000);

 17:

 18:         volatile static Dictionary<Thread, DataContext[]> divDataContext = new Dictionary<Thread, DataContext[]>();

 19:

 20:         static public int DataContextCount { get { return divDataContext.Count; } }

 21:

 22:         static DataContextFactory()

 23:         {

 24:             sysTimer.AutoReset = true;

 25:             sysTimer.Enabled = true;

 26:             sysTimer.Elapsed += new System.Timers.ElapsedEventHandler(sysTimer_Elapsed);

 27:             sysTimer.Start();

 28:         }

 29:

 30:         static void sysTimer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)

 31:         {

 32:             List<Thread> list = new List<Thread>();

 33:             foreach (Thread item in divDataContext.Keys)

 34:             {

 35:                 if (item.ThreadState == ThreadState.Stopped)

 36:                 {

 37:                     list.Add(item);

 38:                 }

 39:             }

 40:             for (int index = 0; index < list.Count; index++)

 41:             {

 42:                 divDataContext.Remove(list[index]);

 43:                 list[index] = null;

 44:             }

 45:             list = null;

 46:         }

 47:

 48:         /// <summary>

 49:         /// 通过工厂的制造模式获取相应的LINQ数据库连接对象

 50:         /// </summary>

 51:         /// <param name="dbName">数据库名称(需要与真实数据库名称保持一致)</param>

 52:         /// <returns>LINQ数据库连接对象</returns>

 53:         public static DataContext Intance(string dbName)

 54:         {

 55:             return Intance(dbName, Thread.CurrentThread);

 56:         }

 57:         /// <summary>

 58:         /// 通过工厂的制造模式获取相应的LINQ数据库连接对象

 59:         /// </summary>

 60:         /// <param name="dbName">数据库名称(需要与真实数据库名称保持一致)</param>

 61:         /// <param name="thread">当前线程引用的对象</param>

 62:         /// <returns>LINQ数据库连接对象</returns>

 63:         public static DataContext Intance(string dbName, Thread thread)

 64:         {

 65:             if (!divDataContext.Keys.Contains(thread))

 66:             {

 67:                 divDataContext.Add(thread, new DataContext[4]);

 68:             }

 69:             if (dbName.Equals("zzl"))

 70:             {

 71:                 if (divDataContext[thread][0] == null)

 72:                 {

 73:                     divDataContext[thread][0] = new Data.LinqzzlDataContext();

 74:                 }

 75:                 return divDataContext[thread][0];

 76:             }

 77:             else

 78:             {

 79:                 return null;

 80:             }

 81:         }

 82:

 83:

 84:

 85:     }

 86: }

 87: