Question

Possible Duplicate:
What is System.Void?
Why not System.Void?

I noticed that it is not allowed to use typeof(System.Void). But typeof(void) is allowed.
When you use typeof(System.String) or typeof(string) there is no difference.

Why is this the case?

Answer 1

This is because C# defines aliases to keep the original C flavor.

The .NET Framework uses specific naming conventions: for instance it states that a class name should start with a Capital. Therefore, String — which is not a C# native type but a .NET class defined in the System namespace — is actually called System.String, or String for short if you have a using System; in your file.

C# defines string as an alias of System.String so that code can look like it does in C and other C-based languages (C++, Java, …). I think it’s more readable. In the same fashion, int is the same as System.Int32.