Win32 dialog helpers

// About dialog : simple implementation
//

class CAboutDialog : public CDialogImpl<CAboutDialog>
{
public:
    enum { IDD = IDD_ABOUT };

    BEGIN_MSG_MAP(CAboutDialog)
        MESSAGE_HANDLER(WM_INITDIALOG, OnInitDialog)
        MESSAGE_HANDLER(WM_CLOSE, OnClose)
        COMMAND_ID_HANDLER(IDOK, OnOK)
        COMMAND_ID_HANDLER(IDCANCEL, OnCancel)
    END_MSG_MAP()

    LRESULT OnInitDialog(UINT uMsg, WPARAM wParam, LPARAM lParam, BOOL& bHandled)
    {
        CenterWindow();
        return TRUE;    // let the system set the focus
    }

    LRESULT OnClose(UINT uMsg, WPARAM wParam, LPARAM lParam, BOOL& bHandled)
    {
        EndDialog(IDCANCEL);
        return 0;
    }

    LRESULT OnOK(WORD wNotifyCode, WORD wID, HWND hWndCtl, BOOL& bHandled)
    {
        EndDialog(IDOK);
        return 0;
    }

    LRESULT OnCancel(WORD wNotifyCode, WORD wID, HWND hWndCtl, BOOL& bHandled)
    {
        EndDialog(IDCANCEL);
        return 0;
    }

};