SilverLight Problem

Question

Hi,

I have a silverlight application,in which there is a combobox in the application.
I want to have different comboitem in the combobox with checkboxes in front of them,user can select multiple cheboxes,and all the comboitem value associated with particular  checkbox should be displayed in the combobox in comma seperated way.

who to acheive this functionality.

Please provide me full code as I am new to silverlight.

Thanks in advance.