The following template works fine if the user presses Enter, although I want the command to fire when the TextBox loses focus as well. How can I do this?
If you don't use any MVVM framework you could use InvokeCommandAction from System.Windows.Interactivity to execute command when event is fired
you'll need to add reference to System.Windows.Interactivity and add namespace in your XAML:
xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"