How to modify the version of the C # language used in Visual Studio

Sometimes, we need to modify the version of the C # language that is currently in use in Visual Studio by modifying the following methods:
In the Solution Explorer, right-click Project, select Properties, switch to Build page, click the ' Advanced ... ' button in the popup Advanced Build Settings dialog box from Lanuage Version drop-down list box, select the C # language you want, please refer to the following illustration. In addition, different versions of the default C # version of VS are as follows:

1. Visual Studio 2015:c# 6.0
2. Visual Studio 2013:c# 5.0
3. Visual Studio 2012:c# 5.0
4. Visual Studio 2010:c# 4.0
5. Visual Studio 2008:c# 3.0
6. Visual Studio 2005:c# 2.0
7. Visual Studio.NET 2003:c# 1.2
8. Visual Studio.NET 2002:c# 1.0

How to modify the version of the C # language used in Visual Studio