VB Forum / Win API / September 2008

  You can see it all in the download I linked, though
that project also has a few other things going on.
EnumChildWindows uses a callback, so it's a bit
awkward. In the following example I use two public
variables that are visible from both the enum function
and the callback function:

Public HCur As Long
Public sClassName As String

You also need these declares:

Private Declare Function GetClassName Lib "user32.dll" Alias "GetClassNameA"
(ByVal hWnd As Long, ByVal lpClassName As String, ByVal nMaxCount As Long)
As Long
Private Declare Function EnumChildWindows Lib "user32" (ByVal hWndParent As
Long, ByVal lpEnumFunc As Long, lParam As Long) As Long

 Then, assuming that you have an IE hWnd, you
use the following to get the actual browser window
from it:

Private Function GetIEServerWindow(ByVal H1 As Long)
  Dim LRet As Long
   HCur = 0
   GetIEServerWindow = 0
   sClassName = "Explorer_Server" ' "Internet Explorer_Server"
   LRet = EnumChildWindows(H1, AddressOf EnumChildProc, 0)
   GetIEServerWindow = HCur  '-- either 0 or handle of browser.
End Function

Public Function EnumChildProc(ByVal hWnd As Long, lParam As Long) As Long
  Dim s2 As String
    s2 = GetWinClass(hWnd)
   If InStr(1, s2, sClassName, 1) > 0 Then
     HCur = hWnd
     EnumChildProc = 0
   Else
     EnumChildProc = 1
   End If
End Function

 Those two functions work together. You send the IE
hWnd into GetIEServerWindow, which calls EnumChildWindows
on that. EnumChildProc is the callback function.
EnumChildWindows will call EnumChildProc for each child
window. EnumChildProc then gets the class name of that
window. If the class name is "Internet Explorer_Server"
it sets the public HCur to the hWnd of that window and
returns 0, causing the enum to quit. Otherwise it returns
1, signaling the enum to continue. By the time it's done
hCur is either a browser window hWnd or 0, if there was
no I E_Server window in the hierarchy.

 The following shows getting the class name of a window
from the hWnd:

Public Function GetWinClass(ByVal H1 As Long) As String
 Dim sBuf As String
 Dim LRet As Long
    On Error Resume Next
      GetWinClass = ""
   sBuf = String$(256, 0)
   LRet = GetClassName(H1, sBuf, Len(sBuf))
    If (LRet > 0) Then GetWinClass = Left$(sBuf, LRet)
End Function

So you send the IE hWnd to GetIEServerWindow and
if non-zero is returned then you send that to GetIEDoc.
That then returns a document object and you're
"ready to roll".  :)

  I'm assuming you have an IE hWnd to start. If not
you'll need to use Shell Object or basic top-level window
enumeration to get it.

  If this all seems confusing you might try starting IE
and then running Spy++. That will let you see the
window hierarchy and see how the actual browser that
has the document, Internet Explorer_Server, is not the
top-level window. I think something like "IEFrame" is
the class name of the top window with the chrome.