So my first attempt did everything out of the code behind, and now I'm trying to refactor my code to use the MVVM pattern, following the guidance of the MVVM in the box information.
I've created a viewmodel class to match my view class, and I'm moving the code out of the code behind into the viewmodel starting with the commands.
My first snag is trying to implement a 'Close' button that closes the window if the data has not been modified. I've rigged up a CloseCommand to replace the 'onClick' method and all is good except for where the code tries to run this.Close(). Obviously, since the code has been moved from a window to a normal class, 'this' isn't a window and therefore isn't closeable. However, according to MVVM, the viewmodel doesn't know about the view, so i can't call view.Close().
Can someone suggest how I can close the window from the viewmodel command?
You don't need to pass the View instance to your ViewModel layer. You can access the main window like this -
Application.Current.MainWindow.Close()
I see no issue in accessing your main window in ViewModel class as stated above. As per MVVM principle there should not be tight coupling between your View and ViewModel i.e. they should work be oblivious of others operation. Here, we are not passing anything to ViewModel from View. If you want to look for other options this might help you - Close window using MVVM