c# - Why System.Array class implements IList but does not provide Add()

Question

This code:

int[] myArr = { 1, 2 };
myArr.Add(3);

throws the following error on Build:

error CS1061: 'System.Array' does not contain a definition for 'Add' and no extension method 'Add' accepting a first argument of type 'System.Array' could be found (are you missing a using directive or an assembly reference?)

IList interface has the Add() method, but why the Array does not implement it?

UPDATE: I see from the answers that it DOES implement it explicitly, OK, I get it, thank you, I should better stick to the question:

Why Array does not actually provide Add(), OR, better, why did it have to implement IList in the first place? Instead of implementing IList, it could be another interface (e.g. IArray) which could have ONLY the useful for Array members of IList -e.g. IsFixedSize, IsReadOnly, IndexOf()... just a thought.

Answer 1

Why Array does not actually provide Add()?

Array has fixed size, so you cannot add new element(s).

The number of dimensions and the length of each dimension are established when the array instance is created. These values can't be changed during the lifetime of the instance. https://msdn.microsoft.com/en-us/library/9b9dty7d.aspx

Why did it have to implement IList in the first place?

Definition of IList: Represents a non-generic collection of objects that can be individually accessed by index.

https://msdn.microsoft.com/en-us/library/system.collections.ilist.aspx

Array is accessed by index and IList accommodate this index, which is why Array implements IList.

For reference: Why array implements IList?