SplitContains.cs

private static bool SplitContains(string values, string value)
        {
            int position = 0;
            foreach (var c in values)
            {
                if (c == ',')
                {
                    if (position == value.Length)
                        return true;
                    else
                        position = 0;
                }
                else if (position != -1)
                {
                    if (value[position] == c)
                        position++;
                    else
                        position = -1;
                }
            }

            return position == value.Length;
        }