Concurrency in C# Cookbook

Chapter 2. Async Basics

This chapter introduces you to the basics of using async and await for asynchronous operations. This chapter only deals with naturally asynchronous operations, which are operations such as HTTP requests, database commands, and web service calls.

If you have a CPU-intensive operation that you want to treat as though it were asynchronous (e.g., so it doesn’t block the UI thread), then see Chapter 3 and Recipe 7.4. Also, this chapter only deals with operations that are started once and complete once; if you need to handle streams of events, then see Chapter 5.

To use async on older platforms, install the NuGet package Microsoft.Bcl.Async into your application. Some platforms support async natively, and some should have the package installed (see Table 2-1):

Table 2-1. Platform support for async

Platform	Dataflow support
.NET 4.5
.NET 4.0	NuGet
Mono iOS/Droid
Windows Store
Windows Phone Apps 8.1
Windows Phone SL 8.0
Windows Phone 7.1	NuGet
Silverlight 5	NuGet

2.1. Pausing for a Period ...