Why in Visual Studio 2015 string.IsNullOrEmpty is better than String.IsNullOrEmpty?

Question

I have been writing String.IsNullOrEmpty for years, and in Visual Studio 2015, the IDE suggests to refactor it into string.IsNullEmpty, Why? what would you do?

I well understand what behind String and string, however, I just wonder why VS 2015 could give me a hint I don't need.

Answer 1

It's due to a "Code Style" option, under:

Tools / Options / Text Editor / C# / Code Style

Uncheck the following option, and it should stop warning you.

If you find the styles useful, in that they force a certain uniformity on your code that you like to be warned about, then leave it checked. Personally, I'd just uncheck it.

Answer 2

The IDE suggests to refactor it into string.IsNullEmpty, Why?

Actually there is no difference between String and string since both are same and string is just an alias. If VS still complaining about re-factoring it then probably because of some FxCop code analysis rules. You may want to verify the same.

In one of my work experience, they had a FxCop custom rule setup to use the actual Type name instead of alias like use String instead of string (OR) Int32 instead of int .