SQL-Abhängigkeit nicht mit Windows-Formular ausgelöst

Question

Ich habe ein Problem mit SQL-Abhängigkeitsproblem mit Windows-Formular-App. Ich habe ein Beispiel gefunden bei source site. Dieses Beispiel funktioniert wie eine C# Terminal-Anwendung, aber wenn ich es als win-Formular-Anwendung modifiziere, feuert es keine SQL-Abhängigkeit.

Hier ist sql db Skript:

USE master 

-- Cleaning up before we start 
IF EXISTS (SELECT name FROM sys.databases WHERE name = N'SqlDependencyTest') 
DROP DATABASE [SqlDependencyTest] 
IF EXISTS (SELECT * FROM sys.server_principals WHERE name = N'startUser') 
DROP LOGIN [startUser] 
IF EXISTS (SELECT * FROM sys.server_principals WHERE name = N'subscribeUser') 
DROP LOGIN [subscribeUser] 

-- Creating a database 
CREATE DATABASE [SqlDependencyTest] 
GO 

-- Ensuring that Service Broker is enabled 
ALTER DATABASE [SqlDependencyTest] SET ENABLE_BROKER 
GO 

-- Creating users 
CREATE LOGIN [startUser] WITH PASSWORD=N'startUser', 
      DEFAULT_DATABASE=[SqlDependencyTest], 
      CHECK_EXPIRATION=OFF, CHECK_POLICY=OFF 
GO 
CREATE LOGIN [subscribeUser] WITH PASSWORD=N'subscribeUser', 
      DEFAULT_DATABASE=[SqlDependencyTest], CHECK_EXPIRATION=OFF, 
      CHECK_POLICY=OFF 
GO 

-- Switching to our database 
use [SqlDependencyTest] 

-- Creating a table. All changes made to the contents of this table will be 
-- monitored. 
CREATE TABLE Users (ID int, Name nvarchar(50)) 
GO 

/* 
* Creating the users in this database 
* 
* We're going to create two users. One called startUser. This is the user 
* that is going to have sufficient rights to run SqlDependency.Start. 
* The other user is called subscribeUser, and this is the user that is 
* going to actually register for changes on the Users-table created earlier. 
* Technically, you're not obligated to make two different users naturally, 
* but I did here anyway to make sure that I know the minimal rights required 
* for both operations 
* 
* Pay attention to the fact that the startUser-user has a default schema set. 
* This is critical for SqlDependency.Start to work. Below is explained why. 
*/ 
CREATE USER [startUser] FOR LOGIN [startUser] 
WITH DEFAULT_SCHEMA = [startUser] 
GO 
CREATE USER [subscribeUser] FOR LOGIN [subscribeUser] 
GO 

/* 
* Creating the schema 
* 
* It is vital that we create a schema specifically for startUser and that we 
* make this user the owner of this schema. We also need to make sure that 
* the default schema of this user is set to this new schema (we have done 
* this earlier) 
* 
* If we wouldn't do this, then SqlDependency.Start would attempt to create 
* some queues and stored procedures in the user's default schema which is 
* dbo. This would fail since startUser does not have sufficient rights to 
* control the dbo-schema. Since we want to know the minimum rights startUser 
* needs to run SqlDependency.Start, we don't want to give him dbo priviliges. 
* Creating a separate schema ensures that SqlDependency.Start can create the 
* necessary objects inside this startUser schema without compromising 
* security. 
*/ 
CREATE SCHEMA [startUser] AUTHORIZATION [startUser] 
GO 

/* 
* Creating two new roles. We're not going to set the necessary permissions 
* on the user-accounts, but we're going to set them on these two new roles. 
* At the end of this script, we're simply going to make our two users 
* members of these roles. 
*/ 
EXEC sp_addrole 'sql_dependency_subscriber' 
EXEC sp_addrole 'sql_dependency_starter' 

-- Permissions needed for [sql_dependency_starter] 
GRANT CREATE PROCEDURE to [sql_dependency_starter] 
GRANT CREATE QUEUE to [sql_dependency_starter] 
GRANT CREATE SERVICE to [sql_dependency_starter] 
GRANT REFERENCES on 
CONTRACT::[http://schemas.microsoft.com/SQL/Notifications/PostQueryNotification] 
    to [sql_dependency_starter] 
GRANT VIEW DEFINITION TO [sql_dependency_starter] 

-- Permissions needed for [sql_dependency_subscriber] 
GRANT SELECT to [sql_dependency_subscriber] 
GRANT SUBSCRIBE QUERY NOTIFICATIONS TO [sql_dependency_subscriber] 
GRANT RECEIVE ON QueryNotificationErrorsQueue TO [sql_dependency_subscriber] 
GRANT REFERENCES on 
CONTRACT::[http://schemas.microsoft.com/SQL/Notifications/PostQueryNotification] 
    to [sql_dependency_subscriber] 

-- Making sure that my users are member of the correct role. 
EXEC sp_addrolemember 'sql_dependency_starter', 'startUser' 
EXEC sp_addrolemember 'sql_dependency_subscriber', 'subscribeUser' 

Hier ist C# win Form Code

using System; 
using System.Collections.Generic; 
using System.ComponentModel; 
using System.Data; 
using System.Data.SqlClient; 
using System.Diagnostics; 
using System.Drawing; 
using System.Text; 
using System.Windows.Forms; 

namespace SqlDependencyTest 
{ 
    public partial class Form1 : Form 
    { 
     private static string mStarterConnectionString = 
@"Data Source=(local);Database=SqlDependencyTest;Persist Security Info=false; 
    Integrated Security=false;User Id=startUser;Password=startUser"; 
     private static string mSubscriberConnectionString = 
    @"Data Source=(local);Database=SqlDependencyTest;Persist Security Info=false; 
Integrated Security=false;User Id=subscribeUser;Password=subscribeUser"; 

     public Form1() 
     { 
      InitializeComponent(); 

      // Quitting if any exist connection... 
      SqlDependency.Stop(mStarterConnectionString); 

      // Starting the listener infrastructure... 

      SqlDependency.Start(mStarterConnectionString); 

      // Registering for changes... 
      RegisterForChanges(); 



     } 

     public void RegisterForChanges() 
     { 
      // Connecting to the database using our subscriber connection string 
      // and waiting for changes... 
      SqlConnection oConnection 
           = new SqlConnection(mSubscriberConnectionString); 
      oConnection.Open(); 
      try 
      { 
       SqlCommand oCommand = new SqlCommand(
        "SELECT ID, Name FROM dbo.Users", 
        oConnection); 
       SqlDependency oDependency = new SqlDependency(oCommand); 
       oDependency.OnChange += new OnChangeEventHandler(OnNotificationChange); 

       SqlDataReader objReader = oCommand.ExecuteReader(); 
       try 
       { 
        while (objReader.Read()) 
        { 
         // Doing something here... 
         labelText.Text = "reading ok"; 
        } 
       } 
       finally 
       { 
        objReader.Close(); 
       } 
      } 
      finally 
      { 
       oConnection.Close(); 
      } 


     } 

     public void OnNotificationChange(object caller, 
              SqlNotificationEventArgs e) 
     { 
      // Testisting if getting dependency response... 
      labelText.Text += e.Info.ToString() + ": " + e.Type.ToString(); 
      RegisterForChanges(); 
     } 

     private void Form1_FormClosed(object sender, FormClosedEventArgs e) 
     { 
      // Quitting... 
      SqlDependency.Stop(mStarterConnectionString); 
     } 
    } 
} 

Answer 1

eigentliche Problem nicht Ereignis Brennen wurde. Problem war "labelText.Text" funktioniert nicht auf Haupt-Thread.

Dieser Code fixiert mein Problem:

labelText.Invoke((MethodInvoker)delegate { 
     labelText.Text = e.Info.ToString() + ": " + e.Type.ToString(); 
    });