SqlDependency가 이벤트를 발생시키지 않거나 트리거하지 않습니다.

Question

SQL Server 데이터베이스의 테이블에서 뭔가 변경되면 내 응용 프로그램에 알림을 보내기위한 자습서를 따라 왔습니다. 이것은 내 리스너 클래스입니다.

class dbListener 
{ 
    public dbListener() 
    { 
     Debug.WriteLine(MainWindow.dbContext.Database.Connection.ConnectionString + "Password=xxx;"); 

     SqlDependency.Stop(MainWindow.dbContext.Database.Connection.ConnectionString + "Password=xxx;"); 
     SqlDependency.Start(MainWindow.dbContext.Database.Connection.ConnectionString + "Password=xxx;"); 
     connection = new SqlConnection(MainWindow.dbContext.Database.Connection.ConnectionString + "Password=xxx;"); 
     connection.Open(); 
     SomeMethod(); 
    } 
    SqlConnection connection; 
    void SomeMethod() 
    { 
     // Assume connection is an open SqlConnection. 
     // Create a new SqlCommand object. 

     SqlCommand command = new SqlCommand("SELECT CODVEI FROM dbo.ArchivioErogazioni", connection); 
     // Create a dependency and associate it with the SqlCommand. 
     command.Notification = null; // ---> DO I NEED IT?? 
     SqlDependency dependency = new SqlDependency(command); 
     // Maintain the refence in a class member. 
     // Subscribe to the SqlDependency event. 
     dependency.OnChange += new OnChangeEventHandler(OnDependencyChange); 
     // Execute the command. 
     command.ExecuteReader(); 
    } 
    // Handler method 
    void OnDependencyChange(object sender, SqlNotificationEventArgs e) 
    { 
     // Handle the event (for example, invalidate this cache entry). 
     MessageBox.Show("ikjkjkj"); 
     Debug.WriteLine("fkldjkfjklgjf"); 
     SomeMethod(); 
    } 

    void Termination() 
    { 
     // Release the dependency. 
     SqlDependency.Stop(MainWindow.GetConnectionString("Model")); 
    } 
} 

이벤트를 올바르게 발생시키지 않습니다. 응용 프로그램의 시작 부분에 메시지 상자가 표시됩니다 (이벤트 관리에서 테스트 함). 한 두 번이나, 이유를 모르겠습니다. 그런 다음 SQL Server Management Studio에서 데이터베이스의 값을 편집 할 때 메시지 상자가 표시되거나 0 또는 1 또는 2 번 표시되면 다시는 실행되지 않습니다. 내 데이터베이스에서

, 나는이 스크립트 실행이 : 나는 분명히 큰 실수 ..... 하나를 수행 한

USE master ; 
GO 
ALTER DATABASE IN4MATICSystem_Pie SET ENABLE_BROKER WITH ROLLBACK IMMEDIATE 
GO 
ALTER AUTHORIZATION ON DATABASE::IN4MATICSystem_Pie to sa; 

을 ??

UPDATE :

class dbListener 
{ 
    public dbListener() 
    { 
     Debug.WriteLine(MainWindow.dbContext.Database.Connection.ConnectionString + "Password=xxx;"); 

     SqlDependency.Stop(MainWindow.dbContext.Database.Connection.ConnectionString + "Password=xxx;"); 
     SqlDependency.Start(MainWindow.dbContext.Database.Connection.ConnectionString + "Password=xxx;"); 
     connection = new SqlConnection(MainWindow.dbContext.Database.Connection.ConnectionString + "Password=xxx;"); 
     connection.Open(); 
     SomeMethod(); 
    } 
    SqlConnection connection; 

    SqlCommand command; 
    void SomeMethod() 
    { 
     // Assume connection is an open SqlConnection. 
     // Create a new SqlCommand object. 

     if (command == null) 
     { 
      command = new SqlCommand("SELECT * FROM dbo.ArchivioErogazioni", connection); 
      // Create a dependency and associate it with the SqlCommand. 
     } 
     else 
     { 
      command.Notification = null; // this cancels any previous notifcation object 
     } 
     SqlDependency dependency = new SqlDependency(command); 
     // Maintain the refence in a class member. 
     // Subscribe to the SqlDependency event. 
     dependency.OnChange += new OnChangeEventHandler(OnDependencyChange); 
     // Execute the command. 
     command.ExecuteReader(); 
    } 
    // Handler method 
    void OnDependencyChange(object sender, SqlNotificationEventArgs e) 
    { 
     if (e.Type == SqlNotificationType.Change) 
     { 
      // Handle the event (for example, invalidate this cache entry). 
      MessageBox.Show("ikjkjkj"); 
      Debug.WriteLine("fkldjkfjklgjf"); 
      SqlDependency dependency = (SqlDependency)sender; 
      dependency.OnChange -= OnDependencyChange; 
      //dependency.OnChange -= OnDependencyChange; 
      SomeMethod(); 
     } 
    } 

    void Termination() 
    { 
     // Release the dependency. 
     SqlDependency.Stop(MainWindow.GetConnectionString("Model")); 
     connection.Close(); 
    } 
} 

Answer 1

: T McKeown의의 힌트 후

, 이것은 내 코드입니다 (아직 작동하지, 그것은 나에게 다음 2 ~ 3 메시지 시작시 상자와 아무것도를 보여줍니다) 이 시도 :

void OnDependencyChange(object sender, SqlNotificationEventArgs e) 
{ 
    // Handle the event (for example, invalidate this cache entry). 
    MessageBox.Show("ikjkjkj"); 
    Debug.WriteLine("fkldjkfjklgjf"); 

    SqlDependency dependency = 
    (SqlDependency)sender; 
    dependency.OnChange -= OnDependencyChange; 
    SomeMethod(); //re-register 
} 

수정 SomeMethod() :

SqlConnection connection; 
SqlCommand command; <-- make command instance var 

void SomeMethod() 
{ 
    // Assume connection is an open SqlConnection. 
    // Create a new SqlCommand object. 

    if (command == null) 
    { 
     command = new SqlCommand("SELECT * FROM dbo.ArchivioErogazioni", connection); 
     // Create a dependency and associate it with the SqlCommand. 
    } 
    else{ 
     command.Notification = null; // this cancels any previous notifcation object 
    } 
    SqlDependency dependency = new SqlDependency(command); 
    // Maintain the refence in a class member. 
    // Subscribe to the SqlDependency event. 
    dependency.OnChange += new OnChangeEventHandler(OnDependencyChange); 
    // Execute the command. 
    command.ExecuteReader(); 
} 

이 함수를 호출하면 true를 반환합니까?

private bool CanRequestNotifications() 
{ 
// In order to use the callback feature of the 
// SqlDependency, the application must have 
// the SqlClientPermission permission. 
try 
{ 
    SqlClientPermission perm = 
     new SqlClientPermission(
     PermissionState.Unrestricted); 

    perm.Demand(); 

    return true; 
} 
catch 
{ 
    return false; 
} 
}