Option Explicit
 
Public Declare Function IsIconic Lib "user32.dll" ( _
   ByVal hwnd As Long) As Long
 
Public Declare Function IsZoomed Lib "user32.dll" ( _
   ByVal hwnd As Long) As Long
 
Public Declare Function ShowWindow Lib "user32.dll" ( _
   ByVal hwnd As Long, _
   ByVal nCmdShow As Long) As Long
 
Public Enum WindowSize
  vbNormalSize = 1
  vbMaximiert = 3
  vbMinimiert = 6
End Enum
 
Public Property Get WindowSize(ByVal hwnd As Long) As WindowSize
  If IsIconic(hwnd) = 1 Then
    WindowSize = vbMinimiert
  ElseIf IsZoomed(hwnd) = 1 Then
    WindowSize = vbMaximiert
  Else
    WindowSize = vbNormalSize
  End If
End Property
 
Public Property Let WindowSize(ByVal hwnd As Long, ByVal State As WindowSize)
  ShowWindow hwnd, State
End Property

Viel Spass,
R@lf