Fixed my Own Problem, just used protected overide subs :)
Like So
Protected Overrides Sub OnNavigatedTo(e As NavigationEventArgs)
MyBase.OnNavigatedTo(e)
cam = New Microsoft.Devices.PhotoCamera()
viewfinderBrush.RelativeTransform = New CompositeTransform() With {.CenterX = 0.5, .CenterY = 0.5, .Rotation = 90}
viewfinderBrush.SetSource(cam)
End Sub
Protected Overrides Sub OnNavigatedFrom(e As NavigationEventArgs)
MyBase.OnNavigatedFrom(e)
If cam IsNot Nothing Then
cam.Dispose()
cam = Nothing
End If
End Sub