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Q141724: Context-Sensitive Help in a CDialog Object

Article: Q141724
Product(s): Microsoft C Compiler
Version(s): winnt:4.0,4.1 4.2,4.2b,5.0
Operating System(s): 
Keyword(s): kbcode kbfile kbsample kbCSHelp kbDlg kbMFC KbUIDesign kbVC420 kbVC500 kbGrpDSMFCATL kb
Last Modified: 31-JUL-2001

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The information in this article applies to:

- The Microsoft Foundation Classes (MFC), used with:
   - Microsoft Visual C++, 32-bit Editions, versions 4.0, 4.1 
   - Microsoft Visual C++, 32-bit Enterprise Edition, version 4.2 
   - Microsoft Visual C++, 32-bit Professional Edition, version 4.2 
   - Microsoft Visual C++, 32-bit Enterprise Edition, version 5.0 
   - Microsoft Visual C++, 32-bit Professional Edition, version 5.0 
   - Microsoft Visual C++, 32-bit Enterprise Edition, version 4.2b 
   - Microsoft Visual C++, 32-bit Professional Edition, version 4.2b 
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This is the 32-bit version of this sample.

SUMMARY
=======

The DLGHLP sample illustrates implementing context-sensitive help in a CDialog
object.

The following files are available for download from the Microsoft Download
Center:

Dlghlp32.exe

For additional information about how to download Microsoft Support files, click
the article number below to view the article in the Microsoft Knowledge Base:

  Q119591 How to Obtain Microsoft Support Files from Online Services

Microsoft used the most current virus detection software available on the date of
posting to scan this file for viruses. Once posted, the file is housed on secure
servers that prevent any unauthorized changes to the file.


Dlghlp32.exe was archived as a self-extracting file using the PKware file-
compression utility. The archived file contains subdirectories, and therefore,
the -d switch needs to be used when decompressing the file to disk.

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

The DLGHLP32 sample implements context-sensitive help in a dialog box by
overriding CWnd::OnHelpInfo and CWnd::OnContextMenu in the dialog class to
handle the WM_HELP and WM_CONTEXTMENU messages. WM_HELP and WM_CONTEXTMENU are
new Win32 messages that are received by the active window when Help is
requested. DLGHLP32 uses the information provided to these handlers to call
::WinHelp with the appropriate parameters.

DLGHLP32 includes two dialog boxes, each with a number of controls in them. The
user is able to set the focus to a particular control and, by pressing F1,
right-clicking, or using the ? (question mark) icon to bring up help that is
specific for that control. Several of the control IDs are used in both dialog
boxes. For example, each dialog box contains a radio button with the ID of
IDC_RADIO1. To allow a unique help context value to be generated for each
control, the ID of each dialog box is used as a base and is added to the ID of
the control.

::WinHelp provides two new help commands for handling WM_HELP and WM_CONTEXTMENU.
They are HELP_WM_HELP and HELP_CONTEXTMENU, respectively. In both cases, an
array mapping control IDs to help contexts is passed in the dwData parameter.
DLGHLP32 defines two of these arrays, one for each dialog box class. This
facilitates generating unique help context for controls in both dialogs, even if
the control IDs are the same.

DLGHLP32 is based on an AppWizard-generated application. Files included with the
sample which are directly related to implementing context- sensitive help in a
dialog box are:

- DLGBOX1.CPP: Implements context-sensitive help for Dialog Box 1 by overriding
  CWnd::OnHelpInfo and CWnd::OnContextMenu.

- DLGBOX2.CPP: Implements context-sensitive help for Dialog Box 2 by overriding
  CWnd::OnHelpInfo and CWnd::OnContextMenu.

- DLGRES.H: Defines the help context IDs based on the ID of the dialog box and
  the specific control.

- DLGCTRLS.HM: Help map file that defines the help context IDs for the dialog
  box controls.

Additional query words: DLGHLP context sensitive

======================================================================
Keywords          : kbcode kbfile kbsample kbCSHelp kbDlg kbMFC KbUIDesign kbVC420 kbVC500 kbGrpDSMFCATL kbDialog 
Technology        : kbAudDeveloper kbMFC
Version           : winnt:4.0,4.1 4.2,4.2b,5.0

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