List list = new List(); list.Add(0); list.Add(new List() { 2, 4, 6 }); list.Add(null);List list = new List(); list.Add(0); list.Add(new List() { 2, 4, 6 }); list.Add(null); list.Add(11); foreach (var item in list) { switch (item) { case 0: break; case IEnumerable test: break; case int n when n > 2: break; case null: break; default: break; } } list.Add(11); foreach (var item in list) { switch (item) { case 0: break; case IEnumerable test: break; case int n when n > 2: break; case null: break; default: break; } }