A method is a member that implements a computation or action that can be performed by an object or class. Methods are declared using method-declarations:

method-declaration

method-header method-body

method-header

attributes_opt method-modifiers_opt return-type member-name ( formal-parameter-list_opt )

method-modifier

method-modifier

method-modifiers method-modifier

method-modifier

new

public

protected

internal

private

static

virtual

sealed

override

abstract

extern

return-type

type

void

member-name

identifier

interface-type . identifier

method-body

block

;

A method-declaration may include a set of attributes (24) and a valid combination of the four access modifiers (17.2.3), the new (17.2.2), static (17.5.2), virtual (17.5.3), override (17.5.4), sealed (17.5.5), abstract (17.5.6), and extern (17.5.7) modifiers.

A declaration has a valid combination of modifiers if all of the following are true:

• The declaration includes a valid combination of access modifiers (17.2.3).
• The declaration does not include the same modifier multiple times.
• The declaration includes at most one of the following modifiers: static, virtual, and override.
• The declaration includes at most one of the following modifiers: new and override.
• If the declaration includes the abstract modifier, then the declaration does not include any of the following modifiers: static, virtual, or extern.
• If the declaration includes the private modifier, then the declaration does not include any of the following modifiers: virtual, override, or abstract.
• If the declaration includes the sealed modifier, then the declaration also includes the override modifier.

The return-type of a method declaration specifies the type of the value computed and returned by the method. The return-type is void if the method does not return a value.

The member-name specifies the name of the method. Unless the method is an explicit interface member implementation (20.4.1), the member-name is simply an identifier. For an explicit interface member implementation, the member-name consists of an interface-type followed by a "." and an identifier.

The optional formal-parameter-list specifies the parameters of the method (17.5.1).

The return-type and each of the types referenced in the formal-parameter-list of a method must be at least as accessible as the method itself (10.5.4).

For abstract and extern methods, the method-body consists simply of a semicolon. For all other methods, the method-body consists of a block, which specifies the statements to execute when the method is invoked.

The name and the formal parameter list of a method define the signature (10.6) of the method. Specifically, the signature of a method consists of its name and the number, modifiers, and types of its formal parameters. The return type is not part of a method's signature, nor are the names of the formal parameters.

The name of a method must differ from the names of all other non-methods declared in the same class. In addition, the signature of a method must differ from the signatures of all other methods declared in the same class.

In This Section:

• 17.5.1: Method parameters
• 17.5.2: Static and instance methods
• 17.5.3: Virtual methods
• 17.5.4: Override methods
• 17.5.5: Sealed methods
• 17.5.6: Abstract methods
• 17.5.7: External methods
• 17.5.8: Method body
• 17.5.9: Method overloading