80 lines
1.6 KiB
C#
80 lines
1.6 KiB
C#
using System;
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using System.Collections.Generic;
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using System.Configuration;
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using System.Linq;
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using System.Text;
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using System.Threading.Tasks;
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namespace Epost.DAL
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{
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public class DB_DLL
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{
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private static DataBaseOpration.OprationSqlDAL db;
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/// <summary>
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/// 程序运行时，创建一个静态只读的进程辅助对象
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/// </summary>
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private static readonly object _object = new object();
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// //SqlLocDPSConnection
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public static string _conn = ConfigurationManager.ConnectionStrings["SqlLocDPSConnection"].ConnectionString;
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/// <summary>
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/// 构造方法私有，外键不能通过New类实例化此类
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/// </summary>
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private DB_DLL()
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{
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}
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/// <summary>
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/// 此方法是本类实例的唯一全局访问点
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/// （双重加锁 Double-Check Locking）
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/// </summary>
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/// <returns></returns>
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public static DataBaseOpration.OprationSqlDAL GetInstance()
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{
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//先判断实例是否存在，不存在再加锁处理
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if (db == null)
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{
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//在同一时刻加了锁的那部分程序只有一个线程可以进入，
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lock (_object)
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{
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//如实例不存在，则New一个新实例，否则返回已有实例
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if (db == null)
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{
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db = new DataBaseOpration.OprationSqlDAL(_conn);
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}
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}
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}
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return db;
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}
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}
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}
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