Windows 8就像使用WPF的模态对话框一样

I am working on a WPF-MVVM (.Net 4.0) application that has a Metro look (it just has a look, it is not a metro application.) I need to show a windows 8 like message box that blocks the operations for the user before he rids that message box by clicking yes/no/cancel (or any button.).I am working on a WPF-MVVM (.Net 4.0) applicati