Public Class Form1
    Declare Auto Function SetWindowLong Lib "user32" (ByVal hWnd As IntPtr, _
      ByVal nIndex As Int32, ByVal dwNewLong As Int32) As IntPtr
    Declare Function SetParent Lib "user32.dll" (ByVal hWndChild As IntPtr, _
    ByVal hWndNewParent As IntPtr) As IntPtr
    Declare Function ShowWindow Lib "user32" (ByVal hWnd As IntPtr, ByVal _
    nCmdShow As Int32) As Boolean
    Const GWL_STYLE As Int32 = -16
    Const SW_MAXIMIZE As Int32 = 3
    Dim Pnl As New Panel With {.Dock = DockStyle.Left, .Width = 500, .Parent = _
      Me}
 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles MyBase.Load
        Me.ClientSize = New Size(800, 600)
        Me.CenterToScreen()
        SetParent(FensterhandleAusMeinerVar, Pnl.Handle)
        SetWindowLong(FensterhandleAusMeinerVar, GWL_STYLE, 0)
        ShowWindow(FensterhandleAusMeinerVar, SW_MAXIMIZE)
    End Sub
End Class