c#: difference between “System.Object” and “object”

string is an alias for global::System.String. It’s simply syntactic sugar. The two are exactly interchangable in almost all cases, and there’ll be no difference in the compiled code.

Personally I use the aliases for variable names etc, but I use the CLR type names for names in APIs, for example:

public int ReadInt32() // Good, language-neutral

public int ReadInt() // Bad, assumes C# meaning of "int"

(Note that the return type isn’t really a name – it’s encoded as a type in the metadata, so there’s no confusion there.)

The only places I know of where one can be used and the other can’t (that I’m aware of) are:

  • nameof prohibits the use of aliases
  • When specifying an enum base underlying type, only the aliases can be used

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