.net - Is List<T> really an undercover Array in C#?

Question

I have been looking at .NET libraries using ILSpy and have come across List<T> class definition in System.Collections.Generic namespace. I see that the class uses methods like this one:

// System.Collections.Generic.List<T>
/// <summary>Removes all elements from the <see cref="T:System.Collections.Generic.List`1" />.</summary>
public void Clear()
{
    if (this._size > 0)
    {
        Array.Clear(this._items, 0, this._size);
        this._size = 0;
    }
    this._version++;
}

So, the Clear() method of the List<T> class actually uses Array.Clear method. I have seen many other List<T> methods that use Array stuff in the body.

Does this mean that List<T> is actually an undercover Array or List only uses some part of Array methods?

I know lists are type safe and don't require boxing/unboxing but this has confused me a bit.

Answer 1

The list class is not itself an array. In other words, it does not derive from an array. Instead it encapsulates an array that is used by the implementation to hold the list's member elements.

Since List<T> offers random access to its elements, and those elements are indexed 0..Count-1, using an array to store the elements is the obvious implementation.