Operator Keywords (C# Reference)
Used to perform miscellaneous actions such as creating objects, checking the run-time type of an object, obtaining the size of a type, and so forth. This section introduces the following keywords:
as Converts an object to a compatible type.
is Checks the run-time type of an object.
sizeof Obtains the size of a type.
typeof Obtains the System.Type object for a type.
stackalloc Allocates a block of memory on the stack.
The following keywords, which can be used as operators and as statements, are covered in the Statements section: