Knowledge Base

FIX: ActiveX Control Events Are Not Fired in ATL Dialog

Article ID: 190530

Article Last Modified on 12/10/2003

Microsoft ActiveX Template Library 3.0, when used with:
- Microsoft Visual C++ 6.0 Enterprise Edition
- Microsoft Visual C++ 6.0 Professional Edition
- Microsoft Visual C++ 6.0 Standard Edition

This article was previously published under Q190530

SYMPTOMS

When you insert an ActiveX control on an ATL dialog box, and add event handlers for it, the event handler is not called.

CAUSE

This problem occurs because the sink objects have not been hooked up to the corresponding ActiveX control [IConnectionPoint::Advise() has not been called for each control].

RESOLUTION

For an ATL dialog box, IConnectionPoint::Advise() can be called for each control on the dialog box, with associated event handlers, by calling AtlAdviseSinkMap(). Add a message handler for WM_INITDIALOG in the dialog box and call AtlAdviseSinkMap(). For example:

   LRESULT OnInitDialog(UINT uMsg, WPARAM wParam, LPARAM lParam,
      BOOL& bHandled)
   {
      // Calls IConnectionPoint::Advise() for each control on the dialog
      // box with sink map entry.
      AtlAdviseSinkMap(this, TRUE);

      return 1;  // Let the system set the focus.
   }

Also, make sure IConnectionPoint::Unadvise() is called for all controls for which IConnectionPoint::Advise() was called. This is done by calling AtlAdviseSinkMap() with the value FALSE for last parameter:

   LRESULT OnDestroy(UINT uMsg, WPARAM wParam, LPARAM lParam,
      BOOL& bHandled)
   {
      // Calls IConnectionPoint::Unadvise() for each control on the dialog
      // box with sink map entry.
      AtlAdviseSinkMap(this, FALSE);

      return 0;
   }

STATUS

Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article.

This problem was corrected in Microsoft Visual C++ .NET.

MORE INFORMATION

Steps to Reproduce Behavior

Create a default ATL AppWizard EXE.
Using the ATL Object Wizard (on the Insert menu, click New ATL Object), insert a dialog box from the miscellaneous category.
In the dialog box resource inserted by the above step, right-click and select "Insert ActiveX Control"; insert an ActiveX control that has an event interface.
Right click the inserted ActiveX control and select Events. In the resulting message/event handler dialog box, add event handlers for the ActiveX control.
Create an instance of the dialog box, and display it through a call to DoModal() or Create().
Build and run the application and cause the ActiveX control to fire the event for which the handler was added in the previous step. Note that the event handler is not called.

Additional query words: kbATL300 kbATL300bug kbATL kbVC600 kbVC600bug

Keywords: kbbug kbfix kbnoupdate kbconnpts kbdlg kbctrl KB190530