Dynamic Drop Shadows in WPF?

Ok I feel like I am just missing something small here, but it has taken me too long to figure this one out.

I have a custom UserControl that has a drop shadow. This UserControl is then used as the view to create a ModelUIElement3D. The drop shadow works 开发者_JAVA百科perfectly when first displaying. The trick here is that I want to be able to change the direction of the shadow programmatically.

I have set up a binding to the ShadowDirection property that I know is working correctly, so I am left to believe that the problem lies in my view not updating. I have tried to invalidate the ModelUIElement3D, the UserControl, and the Window they all sit in, but have had no success.

Anyone know where I might be going wrong?

Thanks in advance.

Rick

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Does the object to which ShadowDirection is bound implement INotifyPropertyChanged?

If not, the UI will never pick up changes from the bound object.