ListSearch<int> listSearch = new ListSearch<int>();

List<int> list = new List<int>(new int[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 });

List<int> subList = new List<int>(new int[] { 4, 5, 6 });

Console.WriteLine("Should return 4  : {0}", listSearch.IndexOf(list, subList));

subList = new List<int>(new int[] { 4, 6, 5 });

Console.WriteLine("Should return -1 : {0}", listSearch.IndexOf(list, subList));

Console.ReadKey();

Here is the code. I had an initial version that used some recursion and worked fine. This version, based on a suggestion by Luke Zhang of Microsoft, is a bit cleaner. Thanks Luke!

public static class ListSearch<T>

{

    public static int IndexOf(List<T> list, List<T> sublist)

    {

        return IndexOf(0, list, sublist);

    }

    public static int IndexOf(int start, List<T> list, List<T> sublist)

    {

        for (int i = start; i <= list.Count - sublist.Count; i++)

        {

            int j = 0;

            while (j < sublist.Count)

            {

                if (!list[i + j].Equals(sublist[j])) break;

                if (j < sublist.Count) j++;

            }

            if (j == sublist.Count) return i;

        }

        return -1;

    }

}