Silverlight scrollviewer's scrollbar invisible when not active

How do i detect when scrolling is unavailable to the scrollviewer control and make it invisible开发者_运维技巧. And the scrollbar only visible when there is a chance to scoll up or down.

Thanks, Shawn McLean

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Specifying HorizontalScrollBarVisibility="Auto" and VerticalScrollBarVisibility="Auto" acheives this goal with out you needing to do any "detecting" of your own.