[C#][Tips] List同士を結合

Public static viod mList_Join()
{
    List<int> il1 = new List<int> { 1, 2, 3 };
    List<int> il2 = new List<int> { 4, 5, 6 };

    List<int> il = il1.Concat(il2).ToList();

    il.ForEach(c => Console.Write(c + ","));
}