Keywords in C#

Keywords in C# Explained

Keywords in C# are the predefined set of reserved words that have special meaning for the compiler. So the keywords cannot be used as identifiers such as variable name, class name, etc. in applications.

 Keywords as Variable Names

 In case you want to use Keywords as variable names (identifiers), then you need to include @ as a prefix for your variable names. For example, @switch is a valid identifier but the switch is not because it’s a keyword and having a special meaning for the compiler.

 The following code example shows how to use the reserved keywords as variable names by including @ as a prefix.

 using System;

namespace CsharpnaijaTutorial

{

    public class @switch

    {

        public int @case;

    }

    class Program

    {

        static void Main(string[] args)

        {

            @switch p1 = new @switch

            {

                @case = 20

            };

            Console.WriteLine("Age: " + p1.@case);

            Console.WriteLine("Press Enter Key to Exit..");

            Console.ReadLine();

        }

    }

}

If we observe above code example, we will see that we used a switch keyword as a variable name (@switch) by including @ as a prefix.

Different types of Keywords in C#

In c#, Keywords are differentiated as two types, those are

a)     Reserve Keywords

b)    Contextual Keywords

Reserved keywords

The table below, lists the available reserved keywords in the C#.

 

abstract	bool	continue	decimal	default
event	explicit	extern	char	checked
class	const	break	as	base
delegate	is	lock	long	num
byte	case	catch	false	finally
fixed	float	for	as	foreach
goto	if	implicit	in	int
interface	internal	do	double	else
namespace	new	null	object	operator
out	override	params	private	protected
public	readonly	sealed	short	sizeof
ref	return	sbyte	stackalloc	static
string	struct	void	volatile	while
true	try	switch	this	throw
unchecked	unsafe	ushort	using	using static
virtual	typeof	uint	ulong	out (generic modifier)

Contextual keywords in C#

Contextual keywords can be used as an identifier in a limited program context and that can be outside of the context.

 

Generally, whenever the new keywords are added to the C# language, those are treated as Contextual keywords in order to avoid the breaking of C# programs which we written in older versions.

 

The table shows the lists of available Contextual Keywords in C#.

 

add	alias	async	await	dynamic
from	get	orderby	ascending	decending
group	into	join	let	nameof
global	partial	set	remove	select
value	var	when	Where	yield