Private Function GridText(ByVal sText As String, ByVal lWidth As Long) As String
  Dim sRight As String
 
  lWidth = lWidth - 90
  If Me.TextWidth(sText) > lWidth Then
    sRight = "..." & Right$(sText, 6)
    sText = Left$(sText, Len(sText) - 6)
 
    lWidth = lWidth - Me.TextWidth(sRight)
    While Me.TextWidth(sText) > lWidth
      sText = Left$(sText, Len(sText) - 1)
    Wend
 
    sText = sText + sRight
  End If
 
  GridText = sText
End Function

<font color=green>' Zeile 10, Spalte 5</font>
With MSFlexGrid1
  .Row = 10: .Col = 5
  .Text = GridText("Mustertext/0815", .ColWidth(5))
End Width