using System;

​

public static class Program

{

​

    private static object o3;

​

    public static void Main()

    {

        Console.WriteLine("Hello World");

​

        Test<DateTimeOffset?> value = new Test<DateTimeOffset?>();

        Console.WriteLine(value.Value == null);

        DateTimeOffset dt1 = new DateTimeOffset(2017, 1, 1, 1, 1, 1, TimeSpan.Zero);

        DateTimeOffset dt2 = new DateTimeOffset(2017, 1, 2, 1, 1, 1, TimeSpan.Zero);

​

        Console.WriteLine(value.TrySetValue(null, dt1));

        Console.WriteLine(value.Value == dt1);

​

        Console.WriteLine(value.TrySetValue(null, dt2));

        Console.WriteLine(value.Value == dt1);

        Console.WriteLine(value.TrySetValue(dt1, dt2));

    }

}

​

public class Test<T>

{

​

​

    public T Value {

        get { return (T)System.Threading.Volatile.Read(ref _value); }

    }

​

​

    private object _value;

    public bool TrySetValue(T oldValue, T newValue)

    {

        object curValObj = System.Threading.Volatile.Read(ref _value);

        if (!object.Equals((T)curValObj, oldValue))

            return false;

        object newValObj = (object)newValue;

        return object.ReferenceEquals(System.Threading.Interlocked.CompareExchange(ref _value, newValObj, curValObj), curValObj);

    }

​

}