Silverlight: How can I built an overview display block for any XAML?

Posted by Ryan Bates on Stack Overflow See other posts from Stack Overflow or by Ryan Bates
Published on 2010-06-11T17:00:10Z Indexed on 2010/06/11 17:02 UTC
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Hi all,

I am trying to create a generic "overview" control for any XAML.

A good example of the desired effect would be on Google Maps or Bing maps: The main map zooms into some content, while a small "overview" block is docked to one of the map corners, showing the user where he/she is zoomed into.

My content is all placed inside a <Canvas>, which can then be scaled and zoomed with transforms. While the user does this kind of navigation, I would like to give them a visual indication of where they are in the larger context of the content.

I have tried to take a 'screenshot' of the XAML before the user starts navigating, i.e. create a WriteableBitmap wbImageData = new WriteableBitmap(TheCanvas, null); and then displaying it in an Image. Based on the user's scrolling and zooming activity, a Rectangle displays which part of the content is currently visible in the display area. This works OK-ish (still clunky), but the image has to be redone everytime the content changes.

Is there a simple way to create this kind of preview, or does anyone know of a component that does it?

Thanks!

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