This article describes how you can create a custom HTML help viewer with Visual FoxPro.

With an understanding of how HTML help URL syntax works combined with the Microsoft WebBrowser control, it is possible to create a relatively simple form in Visual FoxPro that functions as an HTML help viewer.

HTML help files are stored as compressed HTML source in .chm files. Specifically for Visual FoxPro, this file is called FoxHelp.chm, and it contains all of the HTML source and images for the Visual FoxPro help topics. Since the Visual FoxPro help is based on HTML, it can be viewed in Internet Explorer much like any other HTML document. The following code uses the Visual FoxPro HyperLink baseclass to launch Internet Explorer and display the main Visual FoxPro help topic:

   oMyHyperLink = NewObject("Hyperlink")
   cHelpPath = substr(Home(5), 1, Len(Home(5))-8)
   cVFPHelpTopicPath = "mk:@MSITStore:" + cHelpPath + ;
       "FOXHELP.CHM::/html/vfpstartpage.htm"
   oMyHyperLink.NavigateTo(cVFPHelpTopicPath)
				

The following sample code creates a form that contains the Microsoft WebBrowser control, and it automatically navigates to the Visual FoxPro help topic when it is launched. This form does not provide any navigation capabilities outside of those offered within the help topic. However, using the WebBrowser control's extensive object model, it is possible to provide this functionality.

Sample Code

   PUBLIC oMyHelpViewer

   oMyHelpViewer = NewObject("myhtmlhelpviewer")
   oMyHelpViewer.Show

   DEFINE CLASS myhtmlhelpviewer AS form
      Top = 0
      Left = 0
      Height = 454
      Width = 633
      DoCreate = .T.
      BorderStyle = 2
      Caption = "Custom HTML Help Viewer"
      MaxButton = .F.
      WindowState = 0
      Name = "Form1"

      ADD OBJECT olecontrol1 AS olecontrol WITH ;
         Top = 10, ;
         Left = 16, ;
         Height = 433, ;
         Width = 601, ;
         Name = "Olecontrol1", ;
         OLEClass = "Shell.Explorer.2"

      PROCEDURE olecontrol1.Refresh
         NODEFAULT
      ENDPROC

      PROCEDURE olecontrol1.Init
         cHelpPath = SubSTR(Home(5), 1, Len(Home(5))-8)
         cVFPHelpTopicPath = "mk:@MSITStore:" + cHelpPath + ;
                "FOXHELP.CHM::/html/vfpstartpage.htm"
         This.Navigate(cVFPHelpTopicPath)
      ENDPROC
   ENDDEFINE
				

It is important to recognize that although this HTML help viewer allows you to view HTML help topics, it will not provide all of the features and functionality that the Microsoft HTML Help Viewer provides, and there are certain HTML help features that will not work at all when viewing help topics using the WebBrowser control.