MVVM Madness: Commands

Question

I like MVVM. I don\'t love it, but like it. Most of it makes sense. But, I keep reading articles that encourage you to write a lot of code so that you can write XAML and don\'t

Answer 1

I believe that the goal of having "No code in the code-behind" is exactly that, a goal to reach for - not something that you should take as an absolute dogma. There are appropriate places for code in the View - and this isn't necessarily a bad example of where or how code may be simpler than an alternative approach.

The advantage of the other approaches you list, including attached properties or attached events, is that they are reusable. When you hook up an event directly, then do what you did, it's very easy to end up duplicating that code throughout your application. By creating a single attached property or event to handle that wiring, you add some extra code in the plumbing - but it's code that is reusable for any ListView where you want double-click handling.

That being said, I tend to prefer using the more "purist" approach. Keeping all of the event handling out of the View may not effect the testing scenario (which you specifically address), but it does effect the overall designability and maintainability. By introducing code into your code behind, you're restricting your View to always using a ListView with the event handler wired - which does tie your View into code, and restrict the flexibility to redesign by a designer.