Checkbox should be checked/unchecked based on database values using WPF-MVVM

I am working on WPF-MVVM ,I have a user control window where in it contains a combo box and checkbox. The Combo values and Checkbox contents are dynamic. I have the problem in getting the values checked/unchhecked as per the combo box change. It is working properly if its a WPF window but not on User control Window.