Silverlight - Create expanding side panel

I'd like to know how I can make a side panel which when collapsed only shows a button that upon click will be pushed out by an expanded area which contains a control of choice. Clicking the button again will collapse the开发者_JAVA百科 expanded area and the only thing you'll see is the button at the edge of the screen again.

I don't have any good examples of something similar so I hope you understand what I mean.

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in toolbox there is a control called Expander, which is exactly for that purpose