我有以下使用SqlDependency监视我的数据库更改的代码。它工作得很好,但每次运行时都会在数据库中生成自己的带有GUID的队列/服务/路由:
类:
class SqlWatcher
{
private string connectionString;
private string sqlQueue;
private string listenerQuery;
private SqlDependency dependency;
public SqlWatcher(string connectionString, string sqlQueue, string listenerQuery)
{
this.connectionString = connectionString;
this.sqlQueue = sqlQueue;
this.listenerQuery = listenerQuery;
this.dependency = null;
}
public void Start()
{
SqlDependency.Start(connectionString);
ListenForChanges();
}
public void Stop()
{
SqlDependency.Stop(this.connectionString);
}
private void ListenForChanges()
{
//Remove existing dependency, if necessary
if (dependency != null)
{
dependency.OnChange -= onDependencyChange;
dependency = null;
}
SqlConnection connection = new SqlConnection(connectionString);
connection.Open();
SqlCommand command = new SqlCommand(listenerQuery, connection);
dependency = new SqlDependency(command);
// Subscribe to the SqlDependency event.
dependency.OnChange += new OnChangeEventHandler(onDependencyChange);
SqlDependency.Start(connectionString);
command.ExecuteReader();
//Perform this action when SQL notifies of a change
performAction();
connection.Close();
}
private void onDependencyChange(Object o, SqlNotificationEventArgs args)
{
if ((args.Source.ToString() == "Data") || (args.Source.ToString() == "Timeout"))
{
Console.WriteLine(System.Environment.NewLine + "Refreshing data due to {0}", args.Source);
ListenForChanges();
}
else
{
Console.WriteLine(System.Environment.NewLine + "Data not refreshed due to unexpected SqlNotificationEventArgs: Source={0}, Info={1}, Type={2}", args.Source, args.Info, args.Type.ToString());
}
}
private void performAction()
{
Console.WriteLine("Performing action");
}
}
执行:
static void Main(string[] args)
{
string connectionString = @"<MY CONNECTION STRING>";
string sqlQueue = @"NamesQueue";
//Listener query restrictions: http://msdn.microsoft.com/en-us/library/aewzkxxh.aspx
string listenerQuery = "SELECT Value FROM dbo.Table WHERE Name = 'Test'";
SqlWatcher w = new SqlWatcher(connectionString, sqlQueue, listenerQuery);
w.Start();
Thread.Sleep(10000);
w.Stop();
}
我希望通过创建一些队列/服务/路由对象并在程序中调用它们,而不是每次都生成新的对象。
我已经在数据库中创建了这些对象:
CREATE QUEUE NamesQueue;
CREATE SERVICE NamesService ON QUEUE NamesQueue;
CREATE ROUTE NamesRoute WITH SERVICE_NAME = 'NamesService', ADDRESS = 'LOCAL';
然后我修改了我的 C# 代码以使用这个队列和服务:
...
SqlDependency.Start(connectionString, sqlQueue);
...
SqlDependency.Stop(this.connectionString, sqlQueue);
...
dependency = new SqlDependency(command, "service=NamesService;local database=<MY DB>", 0);
...
SqlDependency.Start(connectionString,sqlQueue);
...
进行这些代码更改后,当我运行我的代码时不会创建任何队列,但是我的代码不再起作用,我的应用程序也无法识别对表格/查询所做的更改。
我已经花了几天的时间尝试解决问题,但没有成功,有人可以提供任何建议吗?谢谢。