An easy way to build out hour and minute select list items.

Building Hour and Minute Selections

    class Program
    {
        static void Main(string[] args)
        {
            IEnumerable<int> hours =
                Enumerable.Range(0, 24);

            IEnumerable<int> minutes =
                Enumerable.Range(0, 2).Select(x => x * 30);

            List<string> timeOptions = new List<string>();

            foreach (var hour in hours)
            {
                foreach (var minute in minutes)
                {
                    timeOptions.Add(string.Format("{0}:{1:00}", hour, minute));
                }
            }

            timeOptions.ForEach(s => Console.WriteLine(s));

            Console.ReadLine();

        }
    }