Pandigital Helpers in C#

pandigital.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication4
{
    class Program
    {
        static void Main(string[] args)
        {
            GetPandigitalList(0, 500, 1, 3);
        }

        public static List<long> GetPandigitalList(long startingNum, long endingNum, int panNumStart, int panNumEnd)
        {
            List<long> numberList = new List<long>();

            //int numLength = panNumEnd - panNumStart + 1;

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

            for (int i = panNumStart; i <= panNumEnd; i++)
            {
                startNumStrList.Add(i.ToString());
            }

            long startNum = Convert.ToInt64(String.Join("", startNumStrList.ToArray()));
            long endNum = Convert.ToInt64(String.Join("", startNumStrList.ToArray().Reverse()));

            startNum = (startingNum > startNum) ? startingNum : startNum;
            endNum = (endingNum > endNum) ? endNum : endingNum;

            for (long i = startNum; i <= endNum; i++)
            {
                if (IsPandigital(i, startNumStrList)) numberList.Add(i);
            }

            return numberList;
        }

        public static bool IsPandigital(long candidate, List<string> numList)
        {
            List<char> candidateCharList = candidate.ToString().ToList();
            
            if (candidate.ToString().Length != candidateCharList.Distinct().Count())
            {
                return false;
            }

            List<string> candidateStringList = candidateCharList.Select(x => x.ToString()).ToList();

            if (candidateStringList.Intersect(numList).Count() != candidateStringList.Count)
            {
                return false;
            }

            return true;
        }
    }
}