List.ToArray() - why is the array empty?

Question

I'm writing a serializable object that contains a collection. So, in order to be able to add and remove items from that collection, I added methods that would first convert the collection from an Array into a List, add or remove the items and then convert the List back into a Array.

public void AddElement(Element element) {
   List<Element> list = new List<Element>(this.elements);
   list.Add(element);
   this.elements = list.ToArray();
}

Is there maybe a problem creating the List like this?

List(this.elements)

Or is it a problem, that the Array is Length is 0 at start?

EDIT1: converting from a list field also leaves an empty array.

EDIT2: XML Serialization is not wanted.

tried having a nonserialized private list field in my object. and putting that to the array. the array is still empty. while the list holds 9 items. — globalenemy, May 11 '17 at 09:30
this.elements: is the array field in the object that holds this method — globalenemy, May 11 '17 at 09:31
Is there a particular reason why `this.elements` is not a List? — enkryptor, May 11 '17 at 09:33
J.N. correct me if im wrong. but i thought Lists are not serializable. besides. i told you the length of the array. its 0 — globalenemy, May 11 '17 at 09:33

enkryptor · Accepted Answer · 2017-05-11T12:16:28.367

Your code works fine. Here is the MCVE:

Program.cs

using System;

namespace Test1
{
    class Program
    {
        static void Main(string[] args)
        {
            var test = new TestClass();
            test.AddElement(new Element());
            Console.WriteLine(test.HowMuch());
        }
    }
}

TestClass.cs

using System.Collections.Generic;

namespace Test1
{
    class TestClass
    {
        private Element[] elements = new Element[0];

        public void AddElement(Element element)
        {
            List<Element> list = new List<Element>(this.elements);
            list.Add(element);
            this.elements = list.ToArray();
        }

        public int HowMuch()
        {
            return elements.Length;
        }
    }
}

Element.cs

namespace Test1
{
    class Element
    {
    }
}

The example outputs 1, not 0.

The most probable reason is that you assign this.elements to a variable, hence, store old version of the array.

actually totally right. that does work. found some wrong declerations in my file (**this.** confusion) — globalenemy, May 11 '17 at 09:52

List.ToArray() - why is the array empty?

1 Answers1