Microsoft. Bcl. Async usage summary -- in Net framework 4.5 project Net framework version 4.5 and above can use async/await asynchronous feature in C 5

Under normal circumstances async/await Asynchronous features , Only in .NET Framework 4.5 The above version can only be used , If you want to be in .NET Framework 4 Use C# 5 What about the asynchronous feature in ？ Fortunately, there is an open source class library available --Microsoft.Bcl.Async package , Generally, if you refer to this class library , Need to quote at the same time Microsoft.Bcl.Async Package consists of three libraries ：Microsoft.Bcl、Microsoft.Bcl.Async and Microsoft.Bcl.Build. The specific use is as follows ：

Select project - Right click to manage NuGet Package

Input Microsoft.bcl, Search , find Microsoft.Bcl.Async, Click Install

The interface after installation is as follows ：

  Through the above operations, you can .NET Framework 4.5 Use... On projects .NET Framework 4.5 Version and above can be used C# 5 Medium async/await Asynchronous feature .