is a background worker in a controller async?

Question

Inside an asp.net mvc 2 controller, I have the following code:

using (BackgroundWorker worker = new BackgroundWorker())
                        {
                            worker.DoWork += new DoWorkEventHandler(blah);
                            worker.RunWorkerAsync(var);
                        }

My question is: is this code async, meaning it launches a new thread and the controller returns the view while 'blah' is executing in parallel?

If not, how would I achieve these results?

Answer 1

In MVC 2 there is a new feature called the AsyncController which is the correct way to do async calls in MVC. Your controller should inherit from AsyncController rather than controller. Then you your primary action method name should have "Async" on the end. for example, if you had an action method called Blah(), you name in BlahAsync() instead and this will be automatically recognized by the framework (and use BlahCompleted() for the callback):

public virtual void BlahAsync()
{
    AsyncManager.OutstandingOperations.Increment();
    var service = new SomeWebService();
    service.GetBlahCompleted += (sender, e) =>
        {
            AsyncManager.Parameters["blahs"] = e.Result;
            AsyncManager.OutstandingOperations.Decrement();
        };
    service.GetBlahAsync();
}

public virtual ActionResult BlahCompleted(Blah[] blahs)
{
    this.ViewData.Model = blahs;
    return this.View();
}

More info on the AsyncController here: MVC AsyncController