C# collection

Question

int[] mylist = { 2, 4, 5 };
IEnumerable<int> list1 = mylist;
list1.ToList().Add(1);
// why 1 does not get addedto list1??

Answer 1

Why would it? ToList() generates a new List and the value '1' gets added to it. Since you don't store the return, the new list then gets tossed when it's out of scope.

ToList() doesn't change the original IEnumerable object list1 or give a new representation (it would be called AsList() if it did).

Answer 2

You need to :

int[] mylist = { 2, 4, 5 };
IEnumerable<int> list1 = mylist;
List<int> lst = list1.ToList();
lst.Add(1);
mylist = lst.ToArray();