I am trying to display a login window once my MainWindow loads while sticking to the MVVM pattern. So I am trying to Bind my main windows Loaded event to an event in my view
You're going to have to use the System.Windows.Interactivity dll.
Then add the namespace in your XAML:
xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
Then you can do stuff like:
Please note that you will have to use an ICommand (or DelegateCommand is you use Prism, or RelayCommand if you use MVVMLight), and the DataContext of your Window must hold that ICommand.