I want to use the nameof operator in my C# project in Visual Studio 2015 but the compiler complains with the following message.
Feature 'nameof operator' is not available in C# 5. Please use language version 6 or greater.
I want to know how I can change the C# language version from Visual Studio 2015.
Try this..
Project -> Properties -> Build -> Advanced -> Language Version
Go to Project → Properties → Build → Advanced → Language Version → OK as shown with detail steps and screen shots below:
Follow these steps to change the language version of your project
1: Open your project with Visual Studio 2012, 2013 or 2015, click on View from Menu and then click on Solution Explorer
2: From Solution Explorer, Right Click on the project and Properties from context menu
3: From properties dialog, select the tab Build and click on Advanced button
4: Now, from Advanced Build Settings dialog, select Language Version and click OK button. Thats it.
来源：https://stackoverflow.com/questions/31912651/how-to-change-language-version-in-visual-studio-2015