HOWTO: Add Context-Sensitive Help Button to Win 95 Dialog Boxes

• The Microsoft Foundation Classes (MFC) included with: - Microsoft Visual C++, 32-bit Edition, versions 2.1, 2.2, 4.0, 4.1, 5.0
• Microsoft Visual Studio 97

SUMMARY

Windows 95 provides DS_CONTEXTHELP as a new dialog box style to implement context-sensitive help in dialog boxes. The Dialog Editor included with Visual C++ versions 2.1 and 2.2, does not provide a way to set this style when designing the dialog box. This article shows, by example, how to add the context-sensitive help button to the title bar of dialog boxes.

Starting with version 4.0 of Visual C++, the resource editor does allow this extended style to be set. However, this causes the resource editor to generate a DIALOGEX resource that is not supported on Win32s. Therefore, to stay compatible with Win32s, you can still apply the method discussed in this article.

In Visual C++ version 5.0 and Visual Studio 97, the resource editor allows you set both options.

MORE INFORMATION

If the DS_CONTEXTHELP style is set for a dialog box, Windows 95 adds a question mark button to the title bar of the dialog box. When the user clicks the question mark, the mouse pointer changes to a question mark with a pointer. If the user then clicks a control in the dialog box, the control receives a WM_HELP message.

To set this style, override the OnInitDialog member function of the CDialog-derived class, and add the WS_EX_CONTEXTHELP style to the extended styles for the dialog box. The following code illustrates this:

   BOOL CAboutDlg::OnInitDialog()
   {
        CDialog::OnInitDialog();
        LONG style = ::GetWindowLong(m_hWnd, GWL_EXSTYLE);
        style |= WS_EX_CONTEXTHELP;
        ::SetWindowLong(m_hWnd, GWL_EXSTYLE, style);
        return TRUE;
   }