Anameof expression produces the name of a variable, type, or member as the string constant. Anameof expression is evaluated at compile time and has no effect at run time. When the operand is a type or a namespace, the produced name isn'tfully qualified. The following example shows the use of anameof expression:

Console.WriteLine(nameof(System.Collections.Generic));  // output: GenericConsole.WriteLine(nameof(List<int>));  // output: ListConsole.WriteLine(nameof(List<>)); // output: ListConsole.WriteLine(nameof(List<int>.Count));  // output: CountConsole.WriteLine(nameof(List<int>.Add));  // output: AddList<int> numbers = new List<int>() { 1, 2, 3 };Console.WriteLine(nameof(numbers));  // output: numbersConsole.WriteLine(nameof(numbers.Count));  // output: CountConsole.WriteLine(nameof(numbers.Add));  // output: Add

The preceding example usingList<> is supported in C# 14 and later. You can use anameof expression to make the argument-checking code more maintainable:

public string Name{    get => name;    set => name = value ?? throw new ArgumentNullException(nameof(value), $"{nameof(Name)} cannot be null");}

Beginning with C# 11, you can use anameof expression with a method parameter inside anattribute on a method or its parameter. The following code shows how to do that for an attribute on a method, a local function, and the parameter of a lambda expression:

[ParameterString(nameof(msg))]public static void Method(string msg){    [ParameterString(nameof(T))]    void LocalFunction<T>(T param) { }    var lambdaExpression = ([ParameterString(nameof(aNumber))] int aNumber) => aNumber.ToString();}

Anameof expression with a parameter is useful when you use thenullable analysis attributes or theCallerArgumentExpression attribute.

When the operand is averbatim identifier, the@ character isn't part of the name, as the following example shows:

var @new = 5;Console.WriteLine(nameof(@new));  // output: new

C# language specification

For more information, see theNameof expressions section of theC# language specification, and theC# 11 - Extendednameof scope feature specification.

See also

• C# operators and expressions
• Converttypeof tonameof (style rule IDE0082)