title: WPF MessageBox with MVVM pattern?
body: <p>Say I want to display some validation error to the user. In the MVVM pattern, I could have a label that is bound to some property on my viewmodel. But what if I wanted to show a message box while strictly adhering to the MVVM pattern. What would my viewmodel bind to, and how would it trigger a message box to be created/displayed?</p>