Is the new feature of C# 4.0 - “Optional Parameters” CLS-Compliant?

Question

This new feature is really convenient.

Lately I read the document of the \"Microsoft All-In-One Code Framework\", and it mentions that \"Optional Parameters\" is not CLS

Answer 1

I interpret your question to be about Optional Arguments.

If so then I believe they are CLS-Compliant and you can check by using the CLSCompliant attribute:

using System;

[assembly: CLSCompliant(true)]

namespace ConsoleApplication1
{
    public class Program
    {
        public static int Test(int val=42)
        {
            return val;
        }

        static void Main(string[] args)
        {
            System.Console.WriteLine(Test());
        }
    }
}

This compiles with no warnings.