TPL Task Parallel Library mapping to Async Await

What is async/await?

The async and await keywords were introduced in .NET 4.5 to make calling async methods easier and to make your async code more easily readable. 

The async/await API is syntactic sugar that uses the TPL (Task Parallel Library) behind the scenes. If you wanted to start a new task and have code run on the UI thread after the task completes prior .NET 4.5, your code would have looked something like this:

	// Start a new task (this launches a new thread)
	Task.Factory.StartNew (() => {
	// Do some work on a background thread, allowing the UI to remain responsive
	DoSomething();
	// When the background work is done, continue with this code block
	}).ContinueWith (task => {
	DoSomethingOnTheUIThread();
	// the following forces the code in the ContinueWith block to be run on the
	// calling thread, often the Main/UI thread.
	}, TaskScheduler.FromCurrentSynchronizationContext ());

view raw tpl.cs hosted with ❤ by GitHub

Using async/await, the above code becomes just two lines of it.In the nutshell it does exactly the same thing.

	await DoSomething();
	DoSomethingOnTheUIThread();

view raw asyncawait.cs hosted with ❤ by GitHub

The above code gets compiled behind the scenes to the same TPL code as it does in the first example, so as noted, this is just syntactic sugar, and how sweet it is!