Option Explicit
 
Public Declare Function SendMessage Lib "user32" Alias "SendMessageA" (ByVal _
  hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, ByVal lParam As Long) _
  As Long
Public Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal _
lpClassName As String, ByVal lpWindowName As String) As Long
Public Declare Function FindWindowEx Lib "user32" Alias "FindWindowExA" (ByVal _
hWnd1 As Long, ByVal hWnd2 As Long, ByVal lpsz1 As String, ByVal lpsz2 As _
String) As Long
Public Declare Function SetForegroundWindow Lib "user32" (ByVal hwnd As Long) _
As Long
Public Declare Function GetWindow Lib "user32" (ByVal hwnd As Long, ByVal wCmd _
As Long) As Long
 
 
Public Const WM_CLOSE = &H10
Public Const BM_CLICK = &HF5
 
Public Const GW_HWNDFIRST = 0
Public Const GW_HWNDLAST = 1
Public Const GW_HWNDNEXT = 2
Public Const GW_HWNDPREV = 3
Public Const GW_OWNER = 4
Public Const GW_CHILD = 5

Private Sub Command1_Click()
    Dim hParent     As Long
    Dim hClient     As Long
    Dim lRetVal     As Long
    Dim lZeiger     As Long
    Dim sReport     As String
    '--------------------------
    Dim hRechner    As Long 
    Dim hButton2    As Long
 
    ' Handle des Rechner-Fenster bekommen.
    hParent = FindWindow(vbNullString, "Rechner")
    'wurde handler ermittelt?
    If hParent Then
        hRechner = hParent 'hRechner für später sichern
 
        'Ausgabe des Handler
        sReport = "Parenthandler: &h" & Hex$(hParent) & vbCrLf & vbCrLf
 
        'erstes Child ermitteln
        hParent = GetWindow(hParent, GW_CHILD Or GW_HWNDFIRST)
 
        Do
            'alle Child-Handler ermitteln
            hClient = FindWindowEx(hParent, 0, "", vbNullString)
            sReport = sReport & "Parenthandler " & lZeiger & " : &h" & Hex$( _
              hParent) & vbCrLf
 
            'selectieren eines childes
            Select Case lZeiger
 
                Case 49
                    hButton2 = hParent 'hChild49 für später sichern
                    MsgBox "Handler Taste 2: " & Hex$(hParent)
 
            End Select
 
            'zum nächsten Child
            hParent = GetWindow(hParent, GW_HWNDNEXT)
            lZeiger = lZeiger + 1
        Loop Until hParent = 0
 
        'Ausgabe der handler
        Me.Text1.Text = sReport
 
        ' Fenster aktivieren und in den Vordergrund holen.
        lRetVal = SetForegroundWindow(hRechner)
 
        ' Dann den Button drücken.
        lRetVal = SendMessage(hButton2, BM_CLICK, 0, 0)
    Else
        MsgBox "Der Rechner ist nicht gestartet!"
    End If
 
End Sub