Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (pDest As _
  Any, pSrc As Any, ByVal ByteLen As Long)
 
Private Const H_MAX As Long = &HFFFF + 1
Private Const TTN_FIRST = (H_MAX - 520&)
Private Const WM_NOTIFY = &H4E
Private Const TTN_NEEDTEXTA = (TTN_FIRST - 0&)
Private Const TTN_NEEDTEXT = TTN_NEEDTEXTA
 
Dim sTTBuffer As String
 
Private Type NMHDR
  hWndFrom As Long
  idFrom As Long
  code  As Long
End Type
 
 
Private Type ToolTipText
   hdr As NMHDR
   lpszText As Long
   szText As String * 80
   hInst As Long
   uFlags As Long
End Type

Dim ttt As ToolTipText
Dim hdr As NMHDR
 
Select Case msg
     Case WM_NOTIFY
 
      CopyMemory hdr, ByVal lp, Len(hdr) 
      Select Case hdr.code
      Case TTN_NEEDTEXT  ' tooltip
                     CopyMemory ttt, ByVal lp, Len(ttt)
                     sTTBuffer = StrConv("Hallo " & Slider1.Value, _
                       vbFromUnicode)
                     If (Len(sTTBuffer) > 0) Then
                         sTTBuffer = sTTBuffer & vbNullChar
                         ttt.lpszText = StrPtr(sTTBuffer)
                         CopyMemory ByVal lp, ttt, Len(ttt)
                     End If
      End Select
End Select

Gru?

Ralf