Question

How much memory do an empty string and null take?

I found this question, which tells about the String.Empty memory allocation but not null.

If I want to store an empty string or null in session which one would take less space?

    class MyClass
    {
        public string One { get; set; }
        public string Two { get; set; }            

        public MyClass(string one,string two)
        {
            One = one;
            Two = two;
        }
    } 
    class Main
    {
       var emp = new MyClass(String.Empty, String.Empty);
       var nul = new MyClass(null,null);
    }

Answer 1

Within MyClass, there’ll be absolutely no difference. Both will be “the size of a reference” – either 4 bytes or 8 bytes. It would also take the same amount of space if the values referred to any other strings.

Of course the empty string object takes up space, but it takes up that the same amount of space however many other references there are to it. (In other words, whether you refer to it or not will make no difference to memory… the string.Empty field will still refer to it, so it’s not like it can ever be garbage collected.)