This is a reblog of my article from http://labs.vectorform.com
C# 5.0 comes with the new async/await keywords that make asynchronous code easier to write, read and maintain. This is very nice if you have properly declared methods that support this pattern and Windows Runtime (or WinRT – the API for Windows 8 Metro Style Apps) comes with a lot of these methods for long running tasks or ones of nondeterministic duration – especially in I/O or web calls. It is however completely lacking in support for asynchronous UI development, even though one of the main goals of these new keywords was support for responsive UI.
Interactive coding often introduces the need to start an operation, like an animation or a dialog box and then wait for an event before switching the state of the UI, for example: running another animation or removing a dialog. Reading this article you will learn how to do it better using the upcoming features of C# 5.0, regardless of whether you develop in WinRT, Silverlight, WPF, Windows Forms or even Web Forms. The source code that comes with this article contains a library you can use to cut the amount of code you need to write by half!