BUG: A Visual Basic Application Stops Responding While It Disconnects from the Managed Event Source (827418)

MORE INFORMATION

Steps to Reproduce the Behavior

1. Start Microsoft Visual Studio .NET.
2. On the File menu, point to New, and then click Project.
3. Click Visual Basic Projects under Project Types, and then click Class Library under Templates.
4. In the Name box, type EventSource, and then click OK. By default, Class1 is created.
5. Replace the existing code in the Class1.vb file with the following code:

   Option Explicit On 
   Option Strict On
   
   Imports System
   Imports System.Runtime.InteropServices
   
   Namespace EventSource
       Public Delegate Sub ClickDelegate(ByVal x As Integer, ByVal y As Integer)
   
       ' Step 1: Define the event sink interface (ButtonEvents) that is to be
       ' implemented by the COM sink.
   
       <InterfaceTypeAttribute(ComInterfaceType.InterfaceIsIDispatch)> _
       Public Interface ButtonEvents
           Sub Click(ByVal x As Integer, ByVal y As Integer)
       End Interface
   
       ' Step 2: Connect the event sink interface (ButtonEvents) to a class.
       ' This exposes the ButtonEvents interface as a COM event source.
   
       <ComSourceInterfaces(GetType(ButtonEvents))> _
           Public Class Button
           'Step 3: Declare the event that is to be handled.
           Public Event Click As ClickDelegate
   
           Public Sub CauseClickEvent(ByVal x As Integer, ByVal y As Integer)
               'Step 4: Raise the Click event by using the RaiseEvent statement.
               RaiseEvent Click(x, y)
           End Sub
   
       End Class
   End Namespace
   

6. In Solution Explorer, right-click EventSource, and then click Properties.
7. Expand the Configuration Properties node in the left pane, and then click Build.
8. Click to select the Register for COM Interop check box.
9. In the EventSource Property Pages dialog box, click OK.
10. On the Build menu, click Build Solution.
11. In Microsoft Visual Basic 6.0, create a new Standard EXE project. By default, Form1 is created.
12. On the Project menu, click References.
13. In the References dialog box, click Browse.
14. In the Add Reference dialog box, locate the EventSource project folder on your computer.
15. Click EventSource.tlb in the bin folder, and then click Open.
16. In the References dialog box, click OK.
17. Add a CommandButton control to Form1. By default, Command1 is created.
18. On the View menu, click Code, and then add the following code:

    Option Explicit
    'Use the WithEvents keyword to handle events of EventSource.Button objects.
    Public WithEvents myButton1 As EventSource.Button
    Public WithEvents myButton2 As EventSource.Button
    
    Private Sub Command1_Click()
    'Disconnect myButton1, myButton2 from the event source.
    Set myButton1 = Nothing
    Set myButton2 = Nothing
    MsgBox ("Disconnected from the event source")
    End Sub
    
    Private Sub Form_Load()
    'Set the myButton1 and myButton2 objects to the same instance of EventSource.Button.
    'This connects myButton1 and myButton2 to the event source, that is, the .NET Framework component.
    Set myButton1 = New EventSource.Button
    Set myButton2 = myButton1
    End Sub
    

19. On the File menu, click Save Project.
20. On the Run menu, click Start.
21. Click Command1. Notice that the application stops responding.