Ondrya

///
/// Split a List into smaller lists of N size
/// ref →　http://stackoverflow.com/questions/11463734/split-a-list-into-smaller-lists-of-n-size
///

public static IEnumerable<List<T>> SplitList<T>(List<T> bigList, int nSize = 3)
{
    for (int i = 0; i < bigList.Count; i += nSize)
    {
        yield return bigList.GetRange(i, Math.Min(nSize, bigList.Count - i));