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I am new to C# development and wish to create a more responsive UI. In my preliminary research, I have seen two methods for achieving this:

  1. Multi-threading in conjunction with the BackgroundWorker class.
  2. The newer Async/Await modifiers.

Does newer mean better? What's the difference between the two methods? If I wish to create a new project, how do I choose which method to go with?

EDIT: Maybe I should specify. I am creating a Windows Forms application, where all necessary data will be saved/loaded on the local disk. I will also be communicating with several USB devices.

svick
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robert.ecot
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3 Answers3

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The async and await keywords will not make your application more responsive on their own. They simply make the calling and handling of methods that return Task objects more convenient. In order to make async/await actually use background threads, you will need to combine with the usage of things like:

  • Task.Start() - Starts a given task using the TaskScheduler.
  • PLINQ - Execute a series of operations in parallel, returns a Task.
  • TaskCompletionSource - A custom way to handle async tasks. One place I used this was to handle events coming from a WebBrowser control.
  • Other async methods, such as many of the functions in the Win 8 API.

In other words, async/await is an extension of the Task-Based Asynchronous Pattern. You can find a large host of information, including many samples, here.

The BackgroundWorker is a WinForms component that creates 1 background thread using the Event-Based Asynchronous pattern, and you can populate the work done on this background thread with your own code in the DoWork event handler. In general, Microsoft no longer recommends using this pattern (see the bottom of the page here), though if you are familiar with it already it may still be a simple option.

Another option not mentioned, is the Reactive Extensions for .NET. This is another great framework for adding responsiveness to your apps.

Kevin McCormick
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  • When you say Win 8 API, does that imply the Async features aren't as well-supported on Windows 7 (my target platform)? – robert.ecot Feb 26 '13 at 19:23
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    Hi Robert, the Win 8 .NET API (for "Metro"-style apps) using async and await heavily for everything from File I/O to showing dialog boxes. In other .NET components, for example, FileStream, you can also use async/await with methods like Stream.ReadAsync. So there is some support outside of Win 8, too. – Kevin McCormick Feb 26 '13 at 19:31
  • Great, and thanks for the updated links too! Very helpful. – robert.ecot Feb 26 '13 at 19:47
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    I don't see anything on that page indicating that `BackgroundWorker`, specifically, is recommended against. – Kyralessa Mar 23 '15 at 17:31
  • I also recommend the reading of [Async VS BackgroundWorker](http://www.unknownerror.org/opensource/caolan/async/q/stackoverflow/12414601/async-await-vs-backgroundworker) and the [series of blog posts](http://blog.stephencleary.com/2012/02/async-and-await.html) about **Concurrent programming in C#** of Stephen Clearly, the author of the omonymous book published by O'Reilly. – sentenza Apr 07 '16 at 06:57
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You will be able to accomplish your task using BackgroundWorker. It is a well known class, and many people have used it.

The new C# 5 async and await keywords basically just make it easier to write readable asynchronous code. There may be fewer tutorials and examples of how to accomplish various tasks with these keywords rather than BackgroundWorker.

Unless you need to use an older version of C#, I suggest learning how to use async and await.

sourcenouveau
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I'd say that async-await is much more flexible than BackgroundWorker. And if you want to do something that fits BackgroundWorker, you can do it with async-await too, with more readable and more type-safe code.

Because of that, I think you should prefer using async-await over BackgroundWorker.

svick
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