HostingEnvironment.QueueBackgroundWorkItem和HostingEnvironment.RegisterObject之间的区别

Question

Currently I am using HostingEnvironment.RegisterObject to run my background work in my MVC 5 app. Specifically I have,

public class BackgroundWorker
{
    /// <summary>
    /// Runs a background task that is registered with the hosting environment
    /// so it is guaranteed to finish executing.
    /// </summary>
    /// <param name="action">The lambda expression to invoke.</param>
    public static void Run(Action action)
    {
        new IISBackgroundTask().DoWork(action);
    }

    /// <summary>
    /// Generic object for completing tasks in a background thread
    /// when the request doesn't need to wait for the results 
    /// in the response.
    /// </summary>
    class IISBackgroundTask : IRegisteredObject
    {
        /// <summary>
        /// Constructs the object and registers itself with the hosting environment.
        /// </summary>
        public IISBackgroundTask()
        {
            HostingEnvironment.RegisterObject(this);
        }

        /// <summary>
        /// Called by IIS, once with <paramref name="immediate"/> set to false
        /// and then again with <paramref name="immediate"/> set to true.
        /// </summary>
        void IRegisteredObject.Stop(bool immediate)
        {
            if (_task.IsCompleted || _task.IsCanceled || _task.IsFaulted || immediate)
            {
                // Task has completed or was asked to stop immediately, 
                // so tell the hosting environment that all work is done.
                HostingEnvironment.UnregisterObject(this);
            }
        }

        /// <summary>
        /// Invokes the <paramref name="action"/> as a Task.
        /// Any exceptions are logged
        /// </summary>
        /// <param name="action">The lambda expression to invoke.</param>
        public void DoWork(Action action)
        {
            try
            {
                _task = Task.Factory.StartNew(action);
            }
            catch (AggregateException ex)
            {
                // Log exceptions
                foreach (var innerEx in ex.InnerExceptions)
                {
                    Logger.Log(innerEx);
                }
            }
            catch (Exception ex)
            {
                Logger.Log(ex);
            }
        }

        private Task _task;
        private static readonly ILogger Logger = Loggers.Logger.Instance;
    }
}

usage,

 BackgroundWorker.Run(() => 
       BackGroundMethod();
 );// run this in a background thread

So, using HostingEnvironment.QueueBackgroundWorkItem has any benefit over HostingEnvironment.RegisterObject

Answer 1

QueueBackgroundWorkItem is really just a glorified call to RegisterObject under the covers. It handles converting the call to Stop into a CancellationToken that can be consumed by asynchronous work items, writing to the event log in the case of failures, and a few other bookkeeping items. There's nothing terribly interesting about it. You can use Reflector or ILSpy to browse the source until http://referencesource.microsoft.com/ is updated with the 4.5.2 sources.

If you're comfortable with the complexity of performing all the bookkeeping yourself, there's no reason you can't continue to use RegisterObject . The new API is for consumers who want something a bit simpler.