Microsoft KB Archive/150029

= You must call the AfxEnableControlContainer function when you use OLE control containers in Visual C++ =

Article ID: 150029

Article Last Modified on 6/2/2005

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APPLIES TO


 * Microsoft Visual C++ 4.0 Standard Edition
 * Microsoft Visual C++ 4.1 Subscription
 * Microsoft Visual C++ 4.2 Enterprise Edition
 * Microsoft Visual C++ 5.0 Enterprise Edition
 * Microsoft Visual C++ 6.0 Enterprise Edition
 * Microsoft Visual C++ 4.2 Professional Edition
 * Microsoft Visual C++ 5.0 Professional Edition
 * Microsoft Visual C++ 6.0 Professional Edition
 * Microsoft Visual C++ 6.0 Standard Edition

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This article was previously published under Q150029



SUMMARY
Using Visual C++ version 4.0, it is possible to construct OLE Control Containers. These containers must call AfxEnableControlContainer in their CWinApp::InitInstance. This call is added automatically if OLE Controls support is checked in AppWizard Step 3, but in some cases, this call must be added manually. This article explains why you need to call AfxEnableControlContainer and the possible problems that might occur if this call is not made.



MORE INFORMATION
AfxEnableControlContainer is responsible for wiring up the support structure necessary for a CWnd object to contain an OLE Control. This call is added to a project by AppWizard if OLE Controls support is selected. You need to add this call manually in the following cases:


 * You are adding control container support to an existing project. -or-


 * The object that will contain the OLE controls is not created directly by AppWizard, such as an OLE Control.

For example, if you are dynamically creating an OLE Control as a child of another OLE Control, the parent control must call AfxEnableControlContainer in its constructor.

The following list outlines some of the most common problems (others are possible) that can occur if AfxEnableControlContainer is not called:

  In many cases, you might receive the following TRACE messages in the Output Window of the debugger: >>> If this dialog has OLE controls: >>> AfxEnableControlContainer has not been called yet. >>> You should call it in your app's InitInstance function.   In other cases, you might encounter the following ASSERT in file Cmdtarg.cpp, line 218: ASSERT(afxOccManager != NULL);  If you place a Masked Edit or some other OLE control on a CFormView and then run the application, you might see a message box indicating:

Failed to create empty document.



Additional query words: kbvc410 kbvc400 kbvc500 kbvc600

Keywords: kbhowto kbinfo kbcontainer kbctrl KB150029

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