304notmodified/nameof

Provides strongly typed access to a compile-time string representing the name of a variable, field, property, method, event, enum, or type.

NameOf

NuGet package available at https://www.nuget.org/packages/NameOf.Fody/

Provides strongly typed access to a compile-time string representing the name of a variable, field, property, method, event, enum value, or type.

Other approaches require reflection or traversing the expression tree of a lamdba, each with hits at run-time and less-than-ideal syntax.

This project provides a series of Name.Of... methods to support the cleanest syntax C# currently allows, and with no overhead at run-time. Each instance of the Name.Of... methods you use in your code gets removed and replaced at build time with the intended string. This is done using a technique which is more widely referred to as IL weaving (for more info, check out Fody and Cecil).

Reference to the Name.Of... dummy methods and assembly is removed. Any anonymous methods and fields generated by lambda expressions in some calls to Name.Of... are removed from the assembly as well.

Usage

General purpose

String localVariableName = Name.Of(localVariable); // yields "localVariable"
String propertyName = Name.Of(instanceClass.Property); // yields "Property"
String methodName = Name.Of(StaticClass.SomeMethod); // yields "SomeMethod"
String fieldNameWithoutInstance = Name.Of<InstanceClass>(x => x.Field); // yields "Field"
String nonVoidMethodWithoutInstance = Name.Of<InstanceClass, ReturnType>(x => x.NonVoidMethod); // yields "NonVoidMethod"

Events

String eventName = Name.Of(e => instanceClass.InstanceClassEvent += e); // yields "InstanceClassEvent"
String eventNameWithoutInstance = Name.Of<InstanceClass>((x,e) => x.InstanceClassEvent += e); // yields "InstanceClassEvent"

We need to use this assign syntax because its the only way C# allows us to reference an event outside of its containing type

PropertyChanged events (check out PropertyChanged.Fody for an automatic solution)

private String displayText;
public String DisplayText {
    get { return displayText; }
	set {
	    if (value == displayText)
		    return;
		displayText = value;
		RaisePropertyChanged(Name.Of(DisplayText));
	}
}

ArgumentException throw with argument name

public void Foo(String methodArgument) {
	if (methodArgument == null)
		throw new ArgumentNullException(Name.Of(methodArgument), "String must not be null");
	if (methodArgument.Length < 42)
		throw new ArgumentException("String not long enough", Name.Of(methodArgument)); // Yep, ArgumentException's constructor arguments are in the opposite order of ArgumentNullException's constructor arguments.
	DoSomething();
}

Void methods

String voidMethodName = Name.OfVoid(VoidReturnMethod); // yields "VoidReturnMethod"

We need to use a different method (OfVoid) for a reason best explained by Eric Lippert

The principle here is that determining method group convertibility requires selecting a method from a method group using overload resolution, and overload resolution does not consider return types.

There is a full explanation in a StackOverflow post.

Generic methods

String genericMethodName = Name.Of(instance.GenericMethod<V, R>) // yields "GenericMethod"

V (value) and R (reference) are dummy struct and class types, respectively, for supplying constrained generic arguments

Example signature

public void GenericMethod<T, U>() where T : struct
                                  where U : class {}

Types

String className = Name.Of<InstanceClass>(); // yields "InstanceClass"
String staticClassName = Name.Of(typeof(StaticClass)); // yields "StaticClass"

we have to use the typeof operator because you can't pass a static class as an argument nor generic argument (don't worry; it doesn't actually use reflection - the typeof call is removed during build)

Enums

String enumName = Name.Of<EnumValues>(); // yields "EnumValues"
String enumValueName = Name.Of(EnumValues.FooValue); // yields "FooValue"

EnumValues.FooValue.ToString() uses reflection which is why I have included support for enum values