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Q192984: PRB: ATL Classes Are Not Compatible With ClassWizard

Article: Q192984
Product(s): Microsoft C Compiler
Version(s): WINNT:4.0,4.0a,4.1,4.2,4.2b,5.0,6.0
Operating System(s): 
Keyword(s): kbwizard kbATL kbMFC kbVC400 kbVC410 kbVC420 kbVC500 kbVC600 kbClassWizard kbGrpDSTools
Last Modified: 07-MAY-2001

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The information in this article applies to:

- Microsoft Visual C++, versions 4.0, 4.0a, 4.1 
- Microsoft Visual C++, 32-bit Enterprise Edition, versions 4.2b, 5.0, 6.0 
- Microsoft Visual C++, 32-bit Professional Edition, versions 4.2b, 5.0, 6.0 
- Microsoft Visual C++, 32-bit Learning Edition, version 6.0 
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SYMPTOMS
========

The Visual C++ Resource Editor invokes ClassWizard to add message handlers to an
Active Template Library (ATL) dialog resource. However, ClassWizard does not
recognize classes created with the ATL Object Wizard.

CAUSE
=====

ClassWizard works with MFC classes and does not handle ATL classes or message
maps.

RESOLUTION
==========

Add message maps to ATL classes manually. Use ClassView or the WizardBar to add
member functions and variables.

In Visual C++, version 6.0, WizardBar or ClassView can add generic Windows
messages to ATL classes.


STATUS
======

This behavior is by design.

MORE INFORMATION
================

When you right-click on an ATL class name in ClassView a context menu appears.
From the context menu, select the Add Member Function option to create the
message handler function. A generic message handler function returns an LRESULT
and has this prototype:

     LRESULT OnMsg(UINT uMsg, WPARAM wParam, LPARAM lParam, BOOL& bHandled);

After adding the message handler function prototype, edit the message map
embedded in the class declaration. Add this macro between the BEGIN_MSG_MAP and
END_MSG_MAP macros:

     MESSAGE_HANDLER(message_id, function_name)

Other message map macros are also available. See REFERENCES for articles
explaining the implementation of ATL window objects.

The following sample declaration of an ATL class implements a dialog box and
handles the WM_CTLCOLORDLG message:

     class CDlg : public CDialogImpl<CDlg>
     {
     public:
     CDlg();
     ~CDlg();

     enum { IDD = IDD_DLG };

     BEGIN_MSG_MAP(CDlg)
        MESSAGE_HANDLER(WM_INITDIALOG, OnInitDialog)
        COMMAND_ID_HANDLER(IDOK, OnOK)
        COMMAND_ID_HANDLER(IDCANCEL, OnCancel)
        MESSAGE_HANDLER(WM_CTLCOLORDLG, OnCtlColorDlg)
     END_MSG_MAP()

     LRESULT OnInitDialog(UINT uMsg, WPARAM wParam, LPARAM lParam,
                        BOOL& bHandled);
     LRESULT OnOK(WORD wNotifyCode, WORD wID, HWND hWndCtl, BOOL& bHandled);
     LRESULT OnCancel(WORD wNotifyCode, WORD wID, HWND hWndCtl,
                        BOOL& bHandled);
     LRESULT OnCtlColorDlg(UINT uMsg, WPARAM wParam, LPARAM lParam,
                        BOOL& bHandled);
     };

Steps to Reproduce Behavior
---------------------------

1. Create a new ATL COM AppWizard, using all default settings.

2. On the Insert menu, click New ATL Object.

3. In the ATL Object Wizard, select the Miscellaneous category, and then
  double-click the Dialog object.

4. Type "Dlg" into the Short Name field; click OK.

5. In the ResourceView pane, expand the project name and Dialog.

6. Double-click IDD_DLG.

7. Double-click inside the displayed dialog box.

RESULTS: The ClassWizard appears, and displays a dialog box titled "Adding a
Class". It offers the option of creating a new class or selecting an existing
class to associate with the IDD_DLG dialog resource. Selecting an existing class
does not list the class created by the ATL Object Wizard.

REFERENCES
==========

For more information on adding MFC support to an ATL project, please see the
following article in the Microsoft Knowledge Base:

  Q181505 PRB: ATL COM AppWizard Doesn't Offer MFC Support for .EXE

For additional information, see the following Help topics:

  Visual C++ Online Help: Developer Products; Visual C++; C/C++ Language and
  C++ Libraries; Active Template Library; Articles; ATL Window Classes;
  Implementing a Window

  Visual C++ Online Help: Developer Products; Visual C++; C/C++ Language and C++
  Libraries; Active Template Library; Articles; ATL Window Classes;
  Implementing a Dialog Box

  Visual C++ Online Help: Developer Products; Visual C++; C/C++ Language and C++
  Libraries; Active Template Library; Class Reference; ATL Macros and Global
  Functions

  Visual C++ 6.0 Online Help: Visual C++ Documentation; Reference; Microsoft
  Foundation Class Library and Templates; Active Template Library; Articles;
  ATL Window Classes; Implementing a Window; Adding a Message Handler

======================================================================
Keywords          : kbwizard kbATL kbMFC kbVC400 kbVC410 kbVC420 kbVC500 kbVC600 kbClassWizard kbGrpDSTools 
Technology        : kbVCsearch kbVC400 kbAudDeveloper kbVC410 kbVC500 kbVC600 kbVC32bitSearch kbVC400a kbVC420b kbVC500Search
Version           : WINNT:4.0,4.0a,4.1,4.2,4.2b,5.0,6.0
Issue type        : kbprb

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