' The AddMarginMapping method adds a new property mapping
' for the Margin property.
Private Sub AddMarginMapping()

    elemHost.PropertyMap.Add( _
        "Margin", _
        New PropertyTranslator(AddressOf OnMarginChange))

End Sub


' The OnMarginChange method implements the mapping 
' from the Windows Forms Margin property to the
' Windows Presentation Foundation Margin property.
'
' The provided Padding value is used to construct 
' a Thickness value for the hosted element's Margin
' property.
Private Sub OnMarginChange( _
ByVal h As Object, _
ByVal propertyName As String, _
ByVal value As Object)

    Dim host As ElementHost = h
    Dim p As Padding = CType(value, Padding)
    Dim wpfButton As System.Windows.Controls.Button = host.Child


    Dim t As New Thickness(p.Left, p.Top, p.Right, p.Bottom)

    wpfButton.Margin = t

End Sub

' The AddClipMapping method adds a custom mapping 
' for the Clip property.
Private Sub AddClipMapping()

    wfHost.PropertyMap.Add( _
        "Clip", _
        New PropertyTranslator(AddressOf OnClipChange))

End Sub

' The OnClipChange method assigns an elliptical clipping 
' region to the hosted control's Region property.
Private Sub OnClipChange( _
ByVal h As Object, _
ByVal propertyName As String, _
ByVal value As Object)

    Dim host As WindowsFormsHost = h

    Dim cb As System.Windows.Forms.CheckBox = host.Child

    If cb IsNot Nothing Then
        cb.Region = Me.CreateClipRegion()
    End If

End Sub

' The Window1_SizeChanged method handles the window's 
' SizeChanged event. It calls the OnClipChange method explicitly 
' to assign a new clipping region to the hosted control.
Private Sub Window1_SizeChanged( _
ByVal sender As Object, _
ByVal e As SizeChangedEventArgs)

    Me.OnClipChange(wfHost, "Clip", Nothing)

End Sub

' The CreateClipRegion method creates a Region from an
' elliptical GraphicsPath.
Private Function CreateClipRegion() As [Region] 
    Dim path As New GraphicsPath()
    
    path.StartFigure()
    
    path.AddEllipse(New System.Drawing.Rectangle( _
        0, _
        0, _
        wfHost.ActualWidth, _
        wfHost.ActualHeight))
    
    path.CloseFigure()
    
    Return New [Region](path)

End Function