使用SqlDependency监听SqlServer2005数据库变更通知

直接上代码 ：

声明部分 :

using System;

using System.Collections.Generic;

using System.Text;

using System.Data.SqlClient;

using System.Data;

using System.Configuration;

using System.Windows.Forms;

namespace FrontAlarm

{

public class SQLServiceBroker

{

private string connectionStr = "Data Source=.;Initial Catalog=Test;User ID=cc;Password=cc;";

private string sqlStr = "";

private SqlConnection connection = null;

public delegate void UIDelegate();

private UIDelegate uidel = null;

public Form form = null;

/// <summary>

///

/// </summary>

/// <param name="TableName"></param>

/// <param name="ColumnNames"></param>

public SQLServiceBroker(string TableName, List<string> ColumnNames)

{

string columns = "";

foreach (string str in ColumnNames)

{

if (columns != "")

columns = columns + ",";

columns = columns + "[" + str + "]";

}

this.sqlStr = string.Format("select {0} From [dbo].[{1}]", columns, TableName);

}

/// <summary>

/// </summary>

/// <param name="constr"></param>

/// <param name="TableName"></param>

/// <param name="ColumnNames"></param>

public SQLServiceBroker(string constr, string TableName, List<string> ColumnNames)

: this(TableName, ColumnNames)

{

this.connectionStr = "Data Source=.;Initial Catalog=Test;User ID=cc;Password=cc;";ConfigurationManager.ConnectionStrings[constr].ToString();

}

/// <summary>

///

/// </summary>

~SQLServiceBroker()

{

StopDependency();

connection.Dispose();

}

/// <summary>

///

/// </summary>

/// <returns></returns>

public bool EnoughPermission()

{

SqlClientPermission perm = new SqlClientPermission(System.Security.Permissions.PermissionState.Unrestricted);

try

{

perm.Demand();

return true;

}

catch (System.Exception)

{

return false;

}

}

/// <summary>

///

/// </summary>

/// <param name="uidelegate"></param>

public void InitDependency(UIDelegate uidelegate)

{

SqlDependency.Stop(connectionStr);

SqlDependency.Start(connectionStr);

if (connection == null)

connection = new SqlConnection(connectionStr);

if (!EnoughPermission())

throw new Exception("没有权限（SqlClientPermission）！");

if (uidelegate == null)

throw new Exception("回调方法未指定（UIDelegate）！");

if (connection == null)

throw new Exception("未初始化（InitDependency）！");

this.uidel = uidelegate;

}

/// <summary>

/// 传入窗体对象，以防止委托有需要访问UI层控件是引发的“从不是创建控件的线程访问它”

/// </summary>

/// <param name="form1"></param>

/// <param name="uidelegate"></param>

public void InitDependency(Form form1, UIDelegate uidelegate)

{

InitDependency(uidelegate);

this.form = form1;

}

/// <summary>

///

/// </summary>

public void StartDependency()

{

//这里很奇怪，每次都需要新的command对象

using (SqlCommand command = new SqlCommand(sqlStr, connection))

{

command.Notification = null;

SqlDependency dependency = new SqlDependency(command);

dependency.OnChange += new OnChangeEventHandler(dependency_OnChange);

if (connection.State != ConnectionState.Open)

connection.Open();

command.ExecuteNonQuery();

command.Dispose();

}

}

/// <summary>

///

/// </summary>

public void StopDependency()

{

SqlDependency.Stop(connectionStr);

if (connection != null)

connection.Close();

}

/// <summary>

///

/// </summary>

/// <param name="sender"></param>

/// <param name="e"></param>

private void dependency_OnChange(object sender, SqlNotificationEventArgs e)

{

//注销监测事件

SqlDependency dependency = (SqlDependency)sender;

dependency.OnChange -= dependency_OnChange;

//放在移除事件之后又很大必要，防止ui层调用更新相同表时，进入循环出发调用

//uidel.Invoke();

//uidel();

//使用from.Invoke调用防止访问界面控件引发“从不是创建控件的线程访问它”

if (form != null)

form.Invoke(uidel);

else

uidel();

//再次启动监听

StartDependency();

}

}

}

调用:

SQLServiceBroker broker;

private void DependBrok()

{

//需要监测的列

List<string> columns = new List<string>();

columns.Add("test1");

columns.Add("test2");

string table = "Test";

broker = new SQLServiceBroker(table, columns);

//实例化毁掉函数

SQLServiceBroker.UIDelegate uidel = new SQLServiceBroker.UIDelegate(writeCon);

//初始化，及传入回调函数

broker.InitDependency(uidel);

//初始化，传入窗体对象对于需要委托中访问ui控件的情况

//broker.InitDependency(this, uidel);

//启动监听

broker.StartDependency();

//MessageBox.Show("启动");

}

//监听的数据有变化时触发

private void writeCon()

{

MessageBox.Show("数据有变化o(∩_∩)o 哈哈");

}

关于SqlDependency类，很多人无法测试成功，因为它的限制很多，功能可能有待加强，稍微不注意就会让上面的代码陷入死循环。特别要注意的就是command的sql语句问题:

select id,name from dbo.test where id <>4 order by id desc

很遗憾，他只能支持上面这样的简单语句

列明必须写，不能用*,不能用top，不能用函数，包括聚合函数，不能用子查询，包括where后的子查询，不能用外连接，自连接，不能用临时表，不能用变量，不能用视图，不能垮库，而且表名之前必须加类似dbo这样的前缀....具体有多少限制，基本上除了上述的格式或者比上述更简单的格式，其他的都不可以。

注意

如果在数据库中执行 ‘ALTER DATABASE dbTest SET ENABLE_BROKER ’ 出现死循环 执行下列语句就可以了

ALTER DATABASE dbTest SET NEW_BROKER WITH ROLLBACK IMMEDIATE

ALTER DATABASE dbTest SET ENABLE_BROKER

如果有没成功的 可以给我留言 我解决了这个 希望可以帮到需要的同胞