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;
///
///
///
///
///
public SQLServiceBroker(string TableName, List
{
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);
}
///
///
///
///
///
public SQLServiceBroker(string constr, string TableName, List
: this(TableName, ColumnNames)
{
this.connectionStr = "Data Source=.;Initial Catalog=Test;User ID=cc;Password=cc;";ConfigurationManager.ConnectionStrings[constr].ToString();
}
///
///
///
~SQLServiceBroker()
{
StopDependency();
connection.Dispose();
}
///
///
///
///
public bool EnoughPermission()
{
SqlClientPermission perm = new SqlClientPermission(System.Security.Permissions.PermissionState.Unrestricted);
try
{
perm.Demand();
return true;
}
catch (System.Exception)
{
return false;
}
}
///
///
///
///
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;
}
///
/// 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”
///
///
///
public void InitDependency(Form form1, UIDelegate uidelegate)
{
InitDependency(uidelegate);
this.form = form1;
}
///
///
///
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();
}
}
///
///
///
public void StopDependency()
{
SqlDependency.Stop(connectionStr);
if (connection != null)
connection.Close();
}
///
///
///
///
///
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
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