C# Language Specification

Static and instance methods

When a method declaration includes a static modifier, that method is said to be a static method. When no static modifier is present, the method is said to be an instance method.

A static method does not operate on a specific instance, and it is a compile-time error to refer to this in a static method.

An instance method operates on a given instance of a class, and that instance can be accessed as this (§7.6.7).

When a method is referenced in a member-access (§7.6.4) of the form E.M, if M is a static method, E must denote a type containing M, and if M is an instance method, E must denote an instance of a type containing M.

The differences between static and instance members are discussed further in §10.3.7.

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