using System;

public class Program

{

    public static void Main()

    {

        var a = new Foo();

        a.X = 10;

        a.Reset();

        Console.WriteLine(a.X);

    }

}

​

public struct Foo // class ??

{

    public int X { get; set; }

    public void Reset()

    {

        this = new Foo();   // !!!

    }

}