Question

class Program
{
    static void Main()
    {
        int i = 0;
        whatever x = new whatever(i);
        Console.WriteLine(x);
        i = 1;
        Console.WriteLine(x);
        Console.ReadKey();
    }

    class whatever
    {
       public whatever(object variable)
       {
           this.variable = () => variable.ToString();
       }

       private Func<string> variable;
       public string data;

       public override string ToString()
       {
           data = variable();
           return data;
       }
}

Output:

0
0

what I want to do is get updated i’s value.

Answer 1

Maybe the problem is that delegate is bound to boxed integer data. This is why you change your int and delegate evaluates to old boxed data.

Try it with constructor that takes an int.

But, yes it’s true that ints are pased by value, so this will not work.
Pass delegate to ctor.

class Program
{
        static void Main()
        {
            int i = 0;
        whatever x = new whatever(() => i.ToString());
        Console.WriteLine(x);
        i = 1;
        Console.WriteLine(x);
        Console.ReadKey();
    }

    class whatever
    {
        public whatever(Func<string> someFunc)
        {
            this.variable = someFunc;
        }

        private Func<string> variable;
        public string data;

        public override string ToString()
        {
            data = variable();
            return data;
        }
    }
 }

Output:
0
1

Or as other have indicated:

class Program
{
    static void Main()
    {
        var myRefType = new MyRefType();
        myRefType.MyInt = 0;

        var x = new whatever(myRefType);
        Console.WriteLine(x);
        myRefType.MyInt = 1;

        Console.WriteLine(x);
        Console.ReadKey();
    }

    class whatever
    {
        public whatever(MyRefType myRefType)
        {
            this.variable = () => myRefType.MyInt.ToString();
        }

        private Func<string> variable;

        public override string ToString()
        {
            return variable();
        }
    }

    class MyRefType
    {
        public int MyInt { get; set; }
    }
}

Outputs:
0
1