change field value in a method

   
 

using System;

public class Foo
{
    public int i;
}
   
class RefTest2App
{
    public static void ChangeValue(Foo f)
    {
        f.i = 42;
    }
   
    static void Main(string[] args)
    {
        Foo test = new Foo();
        test.i = 6;
   
        Console.WriteLine("BEFORE METHOD CALL");
        Console.WriteLine("test.i={0}", test.i);
        Console.WriteLine();
   
        ChangeValue(test);
   
        Console.WriteLine("AFTER METHOD CALL");
        Console.WriteLine("test.i={0}", test.i);
    }
}