Will caliburn.micro do the right thing with async method on ViewModel?

The support of asynchronous programming model in Caliburn.Micro is pretty good now.

Few things you can do:

• Use async/await in Action method. Be careful, as action methods are technically event handlers, you shoud do async void rather than async Task.
• Asynchronous event handlers for Screen's events, like Activated, ViewLoaded and other.
• Asynchronous overrides for Screen's methods: OnInitialize, OnActivate, ... You can override then as protected override async void OnInitialize(){} and inside you can await another task.
• Convert Coroutines to Tasks. Use ExecuteAsync() extension method. Coroutines still have some advantages in some scenarios, like execution context.
• IHandleWithTask<TMessage> - pretty handy...

There's a blog post desribing some use cases with few code snippets. And a GitHub repository with sample project I've used to play with async/await in Caliburn.

The answer is 'yes', starting with Caliburn.Micro 1.5.

See release announcement.

It's safe, but will break your existing global exception handling. After I did the refactoring, I didn't see any error dialogues anymore, to fix that, I had to subscribe to the Coroutine.Completed event:

Coroutine.Completed += (s, a) =>{    //Do something here ...};

You can do that in your App.xaml.cs file.

Example from my code on how I handle all possible errors raised in my app:

protected override void OnStartup(StartupEventArgs e){    SetupExceptionHandlers();    base.OnStartup(e);}private void SetupExceptionHandlers(){    AppDomain.CurrentDomain.UnhandledException += (s, a) =>    {        HandleException((Exception)a.ExceptionObject, "AppDomain.CurrentDomain.UnhandledException");    };    Current.DispatcherUnhandledException += (s, a) =>    {        HandleException(a.Exception, "Application.Current.DispatcherUnhandledException");        a.Handled = true;    };    TaskScheduler.UnobservedTaskException += (s, a) =>    {        Dispatcher.InvokeAsync(() => HandleException(a.Exception, "TaskScheduler.UnobservedTaskException"));        a.SetObserved();    };    Coroutine.Completed += (s, a) =>    {        if (a.Error != null)        {            HandleException(a.Error, "Coroutine.Completed");        }    };}private void HandleException(Exception exception, string source){    logger.Error(exception, "Unhandled exception occured (Source: {0})", source);    var msg = new ShowErrorDialogEvent(exception, exception.GetBaseException().Message);    eventAggregator.PublishOnUIThread(msg);}

In-case you're wondering, the logger and eventAggregator variables are instantiated from the bootstrapper class in the OnStartup method before calling DisplayRootViewFor.