C# Keywords

C# Keywords

 

Keywords are predefined, reserved identifiers that have special meanings to the compiler. They cannot be used as identifiers in your program unless they include @ as a prefix. For example, @if is a valid identifier but if is not because if is a keyword.

The first table in this topic lists keywords that are reserved identifiers in any part of a C# program. The second table in this topic lists the contextual keywords in C#. Contextual keywords have special meaning only in a limited program context and can be used as identifiers outside that context. Generally, as new keywords are added to the C# language, they are added as contextual keywords in order to avoid breaking programs written in earlier versions.

abstract

as

base

bool

break

byte

case

catch

char

checked

class

const

continue

decimal

default

delegate

do

double

else

enum

event

explicit

extern

false

finally

fixed

float

for

foreach

goto

if

implicit

in

in (generic modifier)

int

interface

internal

is

lock

long

namespace

new

null

object

operator

out

out (generic modifier)

override

params

private

protected

public

readonly

ref

return

sbyte

sealed

short

sizeof

stackalloc

static

string

struct

switch

this

throw

true

try

typeof

uint

ulong

unchecked

unsafe

ushort

using

virtual

void

volatile

while

 

A contextual keyword is used to provide a specific meaning in the code, but it is not a reserved word in C#. Some contextual keywords, such as partial and where, have special meanings in two or more contexts.

add

alias

ascending

async

await

descending

dynamic

from

get

global

group

into

join

let

orderby

partial (type)

partial (method)

remove

select

set

value

var

where (generic type constraint)

where (query clause)

yield

 

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