'Private Declare Function FindWindow Lib "user32" Alias _
'        "FindWindowA" (ByVal lpClassName As String, ByVal _
'        lpWindowName As String) As Long
 
Private Declare Sub CopyMemory Lib "kernel32" Alias _
        "RtlMoveMemory" (hpvDest As Any, hpvSource As Any, _
        ByVal cbCopy As Long)
 
Private Declare Function SendMessage Lib "user32" Alias _
         "SendMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, _
         ByVal wParam As Long, lParam As Any) As Long
 
Private Declare Function CallWindowProc Lib "user32" Alias _
         "CallWindowProcA" (ByVal lpPrevWndFunc As Long, ByVal _
         hwnd As Long, ByVal Msg As Long, ByVal wParam As Long, _
         ByVal lParam As Long) As Long
 
Public Declare Function SetWindowLong Lib "user32" Alias _
        "SetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As _
        Long, ByVal dwNewLong As Long) As Long
 
Private Type COPYDATASTRUCT
    dwData As Long
    cbData As Long
    lpData As Long
End Type
 
Const GWL_WNDPROC As Long = -4&
Const WM_COPYDATA As Long = &H4A
Dim PrevWndProc As Long
 
Public Sub Init(hwnd As Long)
    PrevWndProc = SetWindowLong(hwnd, GWL_WNDPROC, AddressOf WindowProc)
End Sub
 
Public Sub Terminate(hwnd As Long)
    Call SetWindowLong(hwnd, GWL_WNDPROC, PrevWndProc)
End Sub
 
Public Function SendData(HWnd2 As Long, ByVal WindowName As String, Data As _
  String) As Boolean
    Dim DesthWnd As Long, B(0 To 255) As Byte
    Dim CD As COPYDATASTRUCT
 
    If Data = "" Then Exit Function
 
    DesthWnd = FindWindow(vbNullString, WindowName)
    If DesthWnd = 0 Then
        SendData = False
    Else
        CD.dwData = 1
        Call CopyMemory(B(0), ByVal Data, Len(Data))
        CD.cbData = Len(Data) + 1
        CD.lpData = VarPtr(B(0))
 
        Call SendMessage(DesthWnd, WM_COPYDATA, HWnd2, CD)
        SendData = True
    End If
End Function
 
 
 
Private Function WindowProc(ByVal hwnd As Long, ByVal Msg As Long, ByVal wParam _
  As Long, ByVal lParam As Long) As Long
 
    If Msg = WM_COPYDATA Then
        Dim aa As String, B(0 To 255) As Byte
        Dim CD As COPYDATASTRUCT
 
        Call CopyMemory(CD, ByVal lParam, Len(CD))
 
        Select Case CD.dwData
        Case 1
            Call CopyMemory(B(0), ByVal CD.lpData, CD.cbData)
            aa = StrConv(B, vbUnicode)
            aa = Left$(aa, InStr(1, aa, Chr$(0)) - 1)
            BefehlEmpfangen aa
        End Select
    End If
 
    WindowProc = CallWindowProc(PrevWndProc, hwnd, Msg, wParam, lParam)
End Function