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Call this member function to invoke the WinHelp application.

      virtual void WinHelp(
   DWORD_PTR dwData,


Specifies additional data. The value used depends on the value of the nCmd parameter.


Specifies the type of help requested. For a list of possible values and how they affect the dwData parameter, see the WinHelp Windows function.

The framework also calls this function to invoke the WinHelp application.

The framework will automatically close the WinHelp application when your application terminates.


// Header File: HELPIDS.H
// This example header file is #include'd twice:
// (1) It is #include'd by the .CPP file that passes the DWORD
//     context i.d. to CWinApp::WinHelp.
// (2) It is #include'd in the [MAP] section of the .HPJ file,
//     to associate the help context string "HID_MYTOPIC" with
//     the help context numeric i.d., 101.
// The help context string "HID_MYTOPIC" is what identifies the
// help topic in the help .RTF source file, in the "#" footnote:
//     # HID_MYTOPIC
// Note, it is not necessary to manage help context id's this way
// for help topics associated with command id's and user interface
// id's defined in your RESOURCE.H file; you should use the MAKEHM
// tool via the custom build rule on your resource.h file to produce 
// a help map (.HM) file for these id's.  It is necessary to manage 
// help context id's as illustrated here only for help topics not 
// associated with command id's or user interface id's. 

#define HID_MYTOPIC 101

// Show the custom help topic that has the context string
// "HID_MYTOPIC" in the help .RTF file, and which is mapped
// to the DWORD i.d. HID_MYTOPIC in the above HELPIDS.H file.

// The following is one line of code in the help map (.HM)
// file produced by the MAKEHM tool, which is called by the custom
// build rule on the resource.h file.  The MAKEHM tool reads the 
// following #define in the application's RESOURCE.H file:
#define ID_MYCOMMAND 0x08004
// and adds a help id offset value of 0x10000 to create the
// help context DWORD value 0x18004:
// HID_MYCOMMAND                           0x18004
// See MFC Tech Note 28 for more information on help id offset values.

// Rarely will you need to directly call WinHelp yourself
// with the help context i.d. for a command or user interface
// object. The framework will call WinHelp automatically when
// the user, for example, hits F1 when the focus is on a
// My Command menu item. However, if you do want to directly
// call WinHelp for the help topic associated with the command,
// here is how you would do it:

AfxGetApp()->WinHelp(0x10000 + ID_MYCOMMAND);


Header: afxwin.h