>>Adding an extension method ( say AddCollection) is a bad idea since it accepts an argument of IEnumerable(T).
>>
>>using items.Count() is slow - I guess it uses a foreach loop to count
>>
>>

>>// don't do this at home
>>
>>public static void AddCollection<T>(this List<T> list, IEnumerable<T> items)
>>		{
>>
>>			if (items.Count() <= Tuning.AddRangeMinimumItems) // 128
>>			{
>>				foreach (T item in items)
>>					list.Add(item);
>>			}
>>			else
>>			{
>>				list.AddRange(items);
>>			}
>>		}
>>

>>
>>An extension method that takes a whole array is a better idea - since array.Length is faster
>
>And probably I wouldn't use such an extesnion when it already exists (Concat):
>

>       static void UseConcat()
>        {
>            int[] buf = new int[Size];
>            List<int> list = new List<int>();
>            for (int i = nTimes; --i != 0; )
>            {
>                list.Concat(buf);
>                list.Clear();
>            }
>       }
>

>Cetin


I thought so as well - for a couple of minutes

They are both extension methods - but they are not doing the same, ie one works on the list whereas the other returns another Enumerator