Q&A - How to get the name of Property / Function /

Problem description

Assuming you have an interface / class, and wish to get a Property/Func/Action name, how and what is the best practice to do so?

e.g. given:

public interface IConvertible
{    
    // ...
    bool ToBoolean(IFormatProvider provider);
    // ...
}

How to get the name of 'ToBoolean' method, in a strongly-typed way?

Also, how to get the property name of IsValueCreated from

Lazy<object>.IsValueCreated

Motivation

When you'll do reflection on an interface [method / property / etc], the compiler will help you find all references to it.

For .Net 5 and above: use nameof (credits to m-kazem-akhgary)

For .Net 4.5v and below:

using System;
using System.Linq.Expressions;
using System.Runtime.Remoting.Messaging;
using System.Runtime.Remoting.Proxies;

using Microsoft.VisualStudio.TestTools.UnitTesting;

using LazyHelper = DotNetSandbox.InterfaceNames<System.Lazy<object>>;

namespace DotNetSandbox
{
    // Use case / Example:
    [TestClass]
    public class InterfaceNamesTests
    {
        [TestMethod]
        public void InterfaceNamesTest()
        {
            // Option 1 - Not strongly typed
            string nameA = typeof(IConvertible).GetMethod("ToBoolean").Name;
            Console.WriteLine(nameA);    // OUTPUT: ToBoolean
            string nameB = typeof(Lazy<object>).GetProperty("IsValueCreated").Name;
            Console.WriteLine(nameB);    // OUTPUT: ToBoolean

            // *** Option 2 ***************
            Console.WriteLine();
            Console.WriteLine("Option 2 - Strongly typed way:");
            IConvertible @interface = InterfaceNames<IConvertible>.Create();

            Func<IFormatProvider, bool> func = @interface.ToBoolean;
            string name1 = func.Method.Name;
            Console.WriteLine(name1);   // OUTPUT: ToBoolean

            string propName = InterfaceNames<Lazy<object>>.GetPropertyName(i => i.IsValueCreated);
            Console.WriteLine(propName);   // OUTPUT: IsValueCreated
            //OR (For short version - declare alias using, see using region..)
            string propName2 = LazyHelper.GetPropertyName(i => i.IsValueCreated);
            Console.WriteLine(propName2);   // OUTPUT: IsValueCreated


            // Other options results with complex/unclear code.
        }
    }

    // Helper class
    public class InterfaceNames<T> : RealProxy
    {
        private InterfaceNames() : base(typeof(T)) { }

        public static T Create()
        {
            return (T)new InterfaceNames<T>().GetTransparentProxy();
        }

        public override IMessage Invoke(IMessage msg)
        {
            return null;
        }

        public static string GetName(Delegate d)
        {
            return d.Method.Name;
        }

        public static string GetPropertyName<TProp>(Expression<Func<T, TProp>> prop)
        {
            // Credits to p-s-w-g
            var body = prop.Body as MemberExpression;
            return body == null ? null : body.Member.Name;
        }
    }
}

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