Answer by wild coder for What is the difference between String and string in C#?

First of All, both string& String are not same.There is a difference:String is not a keyword and it can be used as an identifier whereas string is a keyword and cannot be used as identifier.

I am trying to explain with different example :First, when I put string s; into Visual Studio and hover over it I get (without the colour):

That says that string is System.String, right?The documentation is at https://msdn.microsoft.com/en-us/library/362314fe.aspx. The second sentence says "string is an alias for String in the .NET Framework.".