So, what I'm trying to do is access my Form's width and/or height to use in a storyboard. Essentially, I have a Translate Transform animation to slide what are essentially two pages. The animation works fine with hard coded From/To variables, however I need to use soft variables that enable the animation to start from the left/right of my form no matter what size it is. <Storyboard x:Key="SlideLeftToRight" TargetProperty="RenderTransform.(TranslateTransform.X)" AccelerationRatio=".4" DecelerationRatio=".4"> <DoubleAnimation Storyboard.TargetName="PageViewer" Duration="0:0:0.6" From="WindowWidth" To="0"/> <DoubleAnimation Storyboard.TargetName="BorderVisual" Duration="0:0:0.6" From="0" To="NegativeWindowWidth"/> </Storyboard> However, I have no idea how to do so. Any help is greatly appreciated. EDIT: I'm guessing it has something to do with: From="{Binding Width, Source=MainWindow}" However, when I attempt this, I don't know how to make it negative.