How To Call Win32 WinHelp API from Visual Basic

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Step-by-Step Example

1. Create a new Standard EXE project in Visual Basic. Form1 is created by default.
2. Add a CommandButton (Command1) to Form1.
3. Paste the following code into Form1's module:

      Option Explicit
      
      Private Declare Function WinHelp Lib "user32" Alias "WinHelpA" _
         (ByVal hwnd As Long, ByVal lpHelpFile As String, _
         ByVal wCommand As Long, ByVal dwData As Long) As Long
   
      Private Const HELP_CONTENTS = 3
      Private Const HELP_FINDER = 11
   
      Private Sub Command1_Click()
         Dim lResult As Long
         Dim sHelpFile As String
         Dim lCommand as Long, lOption as Long
         sHelpFile = "winfile.hlp"
         lCommand = HELP_CONTENTS
         lOption = 0
         lResult = WinHelp(Me.hwnd, sHelpFile, lCommand, lOption)
      End Sub
   					

4. Run the project and click on the CommandButton. NOTE: The Help Constants topic of the Visual Basic Help file has additional values for the third parameter (command parameter). HELP_CONTENTS is still kept in WinHelp for backward compatibility with 16-bit Help files. The HELP_FINDER command is preferred for 32-bit Help files.