The problem statement: I am tired of thinking how to show a simple message box or user prompt and act based on the response in Model-View-View-Model (MVVM). Common approaches: - It's ok, let's just do this one thing from ViewModel and mock this out for unit testing - Design my own dialog, then what to do from there - Can I write something in view code behind, ah yes, that seems to be the only way out, as anyway MVVM is still not matured...  - and what not?   I am pretty much one among the few frustrated out in this world looking for some convincing answers. I think we can do it a little neater without having the feeling of violating any of our self defined rules! Solution: The Control - Implement a simple control with no designer visibility. - Allow a property to be bound to tell when to show the MessageBox - Provide command binding for possible user actions, Yes, No, Cancel... How do I Use? - Just place the necessary XAML tags in the view - Implement the command for all user actions in the View Model - Run unit tests on the commands