PRB: ATL Classes Are Not Compatible With ClassWizard

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.