FIX: WebBrowser Control Destroyed When Hidden

• Microsoft Internet Explorer (Programming) versions 4.0, 4.01
• The Microsoft Foundation Classes (MFC)
• Internet Client SDK, versions 4.0, 4.01

SYMPTOMS

The Microsoft WebBrowser control is used in a Microsoft Foundation Class (MFC) application and, following the dynamic creation of the control or call to ShowWindow(SW_HIDE), results in the control's methods not functioning or a debug assertion in Winocc.cpp.

CAUSE

If the WebBrowser control is created dynamically without specifying the WS_VISIBLE window style, or if the control's ShowWindow(SW_HIDE) method is called, this results in a call to the control's IOleControl::DoVerb() method with the OLEVERB_HIDE verb. This in turn causes the instance of Internet Explorer to be destroyed, preventing further access to the control's methods, or if built with a debug configuration, the application asserts when CWnd methods are called for the control.

RESOLUTION

Specify the WS_VISIBLE window style when dynamically creating a WebBrowser control and do not call the control's ShowWindow(SW_HIDE) method.

STATUS

Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. This bug was corrected in Microsoft Internet Explorer 5.

MORE INFORMATION

If you need to hide the WebBrowser control, call the Windows SDK ShowWindow() API directly.

Use the following code to hide the control:

::ShowWindow( m_Control.GetSafeHwnd(), SW_HIDE ); 

::ShowWindow( m_Control.GetSafeHwnd(), SW_SHOW ); 

© Microsoft Corporation 1998, All Rights Reserved.
Contributions by Mark Davis, Microsoft Corporation

Additional query words:

Keywords : kbIE400bug kbIE401bug kbIE500fix
Version :
Platform :
Issue type : kbbug