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Displaying HTML help files

Displaying HTML help files

The following code demonstrates a technique for showing HTML help files.

Option Explicit
Private Declare Function HTMLHelp Lib "hhctrl.ocx" Alias "HtmlHelpA" (ByVal hWnd As Long, ByVal lpHelpFile As String, ByVal wCommand As Long, ByVal dwData As Long) As Long
Private Declare Function GetActiveWindow Lib "user32" () As Long
Private Const HH_DISPLAY_TOC = &H1, HH_DISPLAY_INDEX = &H2, HH_DISPLAY_SEARCH = &H3

'Purpose     :  Shows a windows help file (chm file)
'Inputs      :  sHelpFile                   The path to the help file.
'               [lDisplayType]              The section of the help file to display.
'                                           Can be any of the HH_DISPLAY_ constants.
'               [lContextID]                The context ID of the topic to display.
'Outputs     :  Returns the handle of the Help file window on success, else returns zero.
'Notes       :  GetActiveWindow can be replaced by Me.Hwnd in VB


Function HTMLHelpShow(sHelpFile As String, Optional lDisplayType As Long = HH_DISPLAY_TOC, Optional lContextID As Long) As Long
    HTMLHelpShow = HTMLHelp(GetActiveWindow, sHelpFile, lDisplayType, lContextID)
End Function

'Demonstration code
Sub Test()
    'Show Helpfile
    Debug.Print HTMLHelpShow("C:\myhelpfile.chm")
End Sub

'VB Show specific help context
Private Sub Text1_KeyUp(KeyCode As Integer, Shift As Integer)
    If KeyCode = vbKeyF1 Then
        Debug.Print HTMLHelpShow("C:\myhelpfile.chm", , Me.ActiveControl.HelpContextID)
    End If
End Sub

'VBA Show specific help context
Private Sub TextBox1_KeyUp(ByVal KeyCode As MSForms.ReturnInteger, ByVal Shift As Integer)
    If KeyCode = vbKeyF1 Then
        Debug.Print HTMLHelpShow("C:\myhelpfile.chm", , Me.ActiveControl.HelpContextID)
    End If
End Sub