Private WithEvents fSub As frmSub

Private Sub btnInstanzFrmSub_Click(ByVal sender As Object, _
      ByVal e As EventArgs) Handles btnInstanzFrmSub.Click

  If fSub Is Nothing Then
    fSub = New frmSub
    fSub.ParentForm = Me
    fSub.Show()
    Me.btnTextTofrmSub.Enabled = True
  Else
    MessageBox.Show("frmSub ist bereits instanziert!", _
          Nothing, MessageBoxButtons.OK, _
          MessageBoxIcon.Information, _
          MessageBoxDefaultButton.Button1)
  End If
End Sub

Private Sub btnTextTofrmSub_Click(ByVal sender As Object, _
      ByVal e As EventArgs) Handles btnTextTofrmSub.Click
  fSub.txtBoxfrmSub.Text = Me.txtBoxfrmParent.Text
End Sub

Private Sub fSub_Closed(ByVal sender As Object, _
      ByVal e As EventArgs) Handles fSub.Closed
  fSub = Nothing
End Sub

Private boolHide As Boolean = False
Private pForm As frmParent

Shadows Property ParentForm() As frmParent
  Get
    Return pForm
  End Get
  Set(ByVal Value As frmParent)
    pForm = Value
  End Set
End Property

Private Sub frmSub_Location(ByVal sender As Object, _
      ByVal e As EventArgs)

  Dim intLocPointX As Integer = _
        CInt(Screen.PrimaryScreen.WorkingArea.Width / 2)
  Dim intLocPointY As Integer = _
        CInt(Screen.PrimaryScreen.WorkingArea.Height / 2) - _
        CInt(Me.Height / 2)

  Me.Location = New Point(intLocPointX, intLocPointY)
End Sub

Private Sub btnAccess_Click(ByVal sender As Object, _
      ByVal e As EventArgs) Handles btnAccess.Click
  pForm.txtBoxfrmParent.Text = ""
End Sub

Private Sub txtBoxfrmSub_TextChanged(ByVal sender As Object, _
      ByVal e As EventArgs) Handles txtBoxfrmSub.TextChanged
  pForm.txtBoxfrmParent.Text = Me.txtBoxfrmSub.Text
End Sub

Private Sub btnHideShowfrmParent_Click(ByVal sender As Object, _
      ByVal e As EventArgs) Handles btnHideShowfrmParent.Click

  If boolHide Then
    pForm.Show()
    Me.btnHideShowfrmParent.Text = "ParentForm Hide"
    boolHide = False
  Else
    pForm.Hide()
    Me.btnHideShowfrmParent.Text = "ParentForm Show"
    boolHide = True
  End If
End Sub

Private Sub btnBeenden_Click(ByVal sender As Object, _
      ByVal e As EventArgs) Handles btnBeenden.Click
  pForm.Close()
End Sub

Private Sub btnMeClose_Click(ByVal sender As Object, _
      ByVal e As EventArgs) Handles btnMeClose.Click
  pForm.Show()
  pForm.btnTextTofrmSub.Enabled = False
  Me.Close()
End Sub