What is the difference between String and string i

Question

Example (note the case):

string s = "Hello world!";
String s = "Hello world!";

What are the guidelines for the use of each? And what are the differences?

Answer 1

Both are same. But from coding guidelines perspective it's better to use string instead of String. This is what generally developers use. e.g. instead of using Int32 we use int as int is alias to Int32

FYI “The keyword string is simply an alias for the predefined class System.String.” - C# Language Specification 4.2.3 http://msdn2.microsoft.com/En-US/library/aa691153.aspx

Answer 2

Yes, that's no difference between them, just like the bool and Boolean.

Answer 3

It's been covered above; however, you can't use string in reflection; you must use String.

Answer 4

Coming late to the party: I use the CLR types 100% of the time (well, except if forced to use the C# type, but I don't remember when the last time that was).

I originally started doing this years ago, as per the CLR books by Ritchie. It made sense to me that all CLR languages ultimately have to be able to support the set of CLR types, so using the CLR types yourself provided clearer, and possibly more "reusable" code.

Now that I've been doing it for years, it's a habit and I like the coloration that VS shows for the CLR types.

The only real downer is that auto-complete uses the C# type, so I end up re-typing automatically generated types to specify the CLR type instead.

Also, now, when I see "int" or "string", it just looks really wrong to me, like I'm looking at 1970's C code.

Answer 5

There is no difference.

The C# keyword string maps to the .NET type System.String - it is an alias that keeps to the naming conventions of the language.

Similarly, int maps to System.Int32.

Answer 6

string is a keyword, and you can't use string as an identifier.

String is not a keyword, and you can use it as an identifier:

Example

string String = "I am a string";

The keyword string is an alias for System.String aside from the keyword issue, the two are exactly equivalent.

 typeof(string) == typeof(String) == typeof(System.String)