Dynamically use resource dictionary

Question

I am new to Silverlight. In my project, I designed main page and controls with several colour combination and kept in separate xaml file as Resource Dictionary. I have multiple xaml files of Resource Dictionary. I assigned all colour combinations names (Resource Dictionary) to one combo box. I want to change the colour combination of my main page, as per selection of combo box. Kindly guide me on the above issue.

Thanks
Anil