How To Help95.exe Implements Windows 95 Style Help (167698)
The information in this article applies to:
- The Microsoft Foundation Classes (MFC), when used with:
- Microsoft Visual C++, 32-bit Enterprise Edition 4.2
- Microsoft Visual C++, 32-bit Enterprise Edition 4.2b
- Microsoft Visual C++, 32-bit Enterprise Edition 5.0
- Microsoft Visual C++, 32-bit Enterprise Edition 6.0
- Microsoft Visual C++, 32-bit Professional Edition 4.2
- Microsoft Visual C++, 32-bit Professional Edition 4.2b
- Microsoft Visual C++, 32-bit Professional Edition 5.0
- Microsoft Visual C++, 32-bit Professional Edition 6.0
- Microsoft Visual C++, 32-bit Learning Edition 6.0
This article was previously published under Q167698 SUMMARY Windows 95 provides support for context-sensitive help by
means of the messages WM_HELP and WM_CONTEXTMENU. It also provides a style
called WS_EX_CONTEXTHELP that has the effect of adding a question mark button
to the windows caption bar of a dialog. The HELP95 sample shows how these
messages can be used to show context Help for a window. The sample
includes the file help95.hpj that should contain one of the following lines:
#include <c:\msdev\mfc\include\afxhelp.hm> // for Visual C++ 4.x
#include <c:\devstudio\VC\MFC\include\afxhelp.hm> // for Visual C++ 5.0
#include <c:\program files\microsoft visual studio\vc98\MFC
\include\afxhelp.hm> // for Visual C++ 6.0
#include C:\Program Files\Microsoft Visual Studio .NET\Vc7\atlmfc\include\afxhelp.hm // for VC.NET
Make sure the line reflects the correct version of Visual C++ that is
installed and that it contains the correct path to afxhelp.hm.
The following
files are available for download from the Microsoft Download
Center: For
additional information about how to download Microsoft Support files, click the
following article number to view the article in the Microsoft Knowledge Base: 119591 How to Obtain Microsoft Support Files from Online Services
Microsoft scanned this file for viruses. Microsoft used the most
current virus-detection software that was available on the date that the file
was posted. The file is stored on security-enhanced servers that help to
prevent any unauthorized changes to the file.
NOTE: Use the -d option when running HELP95.EXE to
decompress the file and recreate the proper directory structure. MORE INFORMATION In 16-bit MFC, applications implemented context-sensitive
Help by using the accelerator keys F1 and SHIFT+F1 that generated WM_COMMAND
messages with IDs ID_HELP and ID_CONTEXTHELP, respectively. This, together with
the MFC private messages WM_COMMANDHELP and WM_HELPHITEST, was used to bring up
context Help for an application.
Windows 95 makes this process
easier by providing the WM_HELP message that gets sent each time the user
presses the F1 key, giving the application a chance to bring up Help
information on the control that has the keyboard focus or on the dialog box
itself. This WM_HELP message is not limited to dialog boxes alone; it gets sent
to any window that has keyboard focus or to the currently active window.
Windows 95 also provides the style WS_EX_CONTEXTHELP that adds a
question mark button to a dialog's caption bar. When a user clicks this button,
the cursor changes to a question mark with a pointer. If the user then clicks a
control on the dialog box, a WM_HELP message is sent to it. The control passes
this message on to its parent, which should then handle this message and call
WinHelp() with HELP_WM_HELP. This displays a pop-up window with the Help text
for the control.
There is also the WM_CONTEXTMENU message that gets
sent whenever the user right-clicks a window. This message is typically used to
display a pop-up menu using TrackPopupMenu(). It can also be used to display
context Help by calling WinHelp() with the parameter HELP_CONTEXTMENU. This has
the effect of displaying a pop-up menu with a "What's This?" entry. Selecting
this option then displays a pop-up window with Help text for the window.
HELP95 is an MFC MDI application with form views for MDI child
windows. The application shows how to bring up context Help for form views,
dialogs, common dialogs, and property sheets.
Context Help for
dialogs and form views is pretty straight-forward. It requires that the user
handle the WM_HELP or WM_CONTEXTMENU message and call WinHelp(). Make sure the
Help ID is checked for each of the controls in the resource editor. In case of
WM_HELP message, the lParam points to a HELPINFO structure that contains
information about the menu item, control, dialog box, or window for which help
is requested. For WM_CONTEXTMENU messages, there is no HELPINFO structure with
all the information so the API calls GetDlgCtrlID() and
GetWindowContextHelpId() are needed to give the required information.
In case of property sheets, it is slightly more complicated. Adding
Help IDs to controls on a Property page using the resource editor causes it to
use the DIALOGEX resource instead of the DIALOG resource. But Windows does not
support the creation of Property sheets with the DIALOGEX resource. To work
around this, the Help IDs are added programmatically after the creation of the
property sheet and property pages. Also, because there is no property sheet
template, the WS_EX_CONTEXTHELP style has to be set programmatically. The
handling of the WM_HELP and WM_CONTEXTMENU messages remains the same.
NOTE: If you are using VS.NET, you may receive a warning about
Enable3DControls being deprecated. You can safely ignore this warning.
REFERENCES MFC Technical Note 28: "Context-Sensitive Help Support"
For more information, please see the following articles in the
Microsoft Knowledge Base: 149343
How To Implement Context-Sensitive Help for Dialog Controls
138505
How To Add Context-Sensitive Help Button to Windows 95 Dialogs
140676
PRB: ClassWizard Uses WM_HELPINFO Instead of WM_HELP
| Modification Type: | Minor | Last Reviewed: | 8/5/2004 |
|---|
| Keywords: | kbdownload kbcode kbCSHelp kbfile kbhowto kbSample KB167698 |
|---|
|