using System;

public class Program

{

    public class MyObject

    {

        public int Value;

    }

​

    public static void Main()

    {

        MyObject m1 = new MyObject();

        MyObject m2 = new MyObject();

        DoWork(m1);

        DoWorkByRef(ref m2);

        Console.WriteLine("Object1 is null: {0}", m1 == null);

        if (m1 != null)

        {

            Console.WriteLine("Object1.Value={0}", m1.Value);

        }

        Console.WriteLine("Object2 is null: {0}", m2 == null);

        if (m2 != null)

        {

            Console.WriteLine("Object2.Value={0}", m2.Value);

        }

    }

​

    public static void DoWork(MyObject o)

    {

        o.Value = 3;

        o = null;

    }

​

    public static void DoWorkByRef(ref MyObject o)

    {

        o.Value = 3;

        o = null;

    }

}