Question

How do I get the Windows Handle of an ActiveDocument in Microsoft Word?

I wish to save the handle value to a variable.

Answer 1

You can use the FindWindow function to get the handle of the window in a currently active word application:

Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" _
(ByVal lpClassName As String, ByVal lpWindowName As String) As Long

The class name for MS Word is “OpusApp”. If you have only the one Word app open then the following would return the handle to that window:

Public Function Test1()
Dim lhWnd As Long
lhWnd = FindWindow("OpusApp", vbNullString)
End Function

Note when you have multiple active Word applications, you can add the name of the window caption. For example if its saved as “Stanigator.doc”, then the caption would read as “Stanigator – Microsoft Word”. So:

Public Function Test2()
Dim lhWnd As Long
lhWnd = FindWindow(vbNullString, "Stanigator - Microsoft Word")
End Function

The other API that may come in handy is:

Private Declare Function GetActiveWindow Lib "user32" () As Long

Edit:

I was going to recommend the VSTO approach but based on this link that doesn’t appear to be wise:
Connect Issue: VSTO API support for MS Word Main Window Handle