Concat two string arrays into one collection without duplicates

iJunior_C#_Lesson_36

using System.Collections;
using System.Diagnostics;
using System.Text;

namespace iJuniorPractice;

class Program
{
    static void Main(string[] args)
    {
        string[] arrayOne = { "1", "2", "4" };
        string[] arrayTwo = { "1", "2", "6", "8" };

        List<int> result = new List<int>();
        StringArrayToIntList(result, arrayOne);
        StringArrayToIntList(result, arrayTwo);
        WriteListObjects(result);
    }

    static void StringArrayToIntList(List<int> list, string[] array)
    {
        foreach (var value in array)
        {
            if(int.TryParse(value, out int number) && list.Contains(number) == false)
                list.Add(number);
        }
    }

    static void WriteListObjects(List<int> numbersList)
    {
        foreach (var value in numbersList)
        {
            Console.Write(value);
        }
    }
}

solution via HashSet:

namespace iJuniorPractice;

class Program
{

static void Main(string[] args)
    {
        string[] arrayOne = { "1", "2", "4" };
        string[] arrayTwo = { "1", "2", "6", "8" };
        
        HashSet<int> result = GetUniqueHashSet(ParseToIntList(arrayOne), ParseToIntList(arrayTwo));
        WriteHashObjects(result);
    }

static List<int> ParseToIntList(string[] array)
    {
        List<int> result = new List<int>();

        foreach (var value in array)
        {
            if(int.TryParse(value, out int number))
                result.Add(number);
        }

        return result;
    }

static void WriteHashObjects(HashSet<int> numbersList)
    {
        foreach (var value in numbersList)
        {
            Console.Write(value);
        }
    }

static HashSet<int> GetUniqueHashSet(List<int> listOne, List<int> listTwo)
    {
        HashSet<int> uniqueList = new HashSet<int>();

        FillHashSetByList(listOne, uniqueList);
        FillHashSetByList(listTwo, uniqueList);

        return uniqueList;
    }

static void FillHashSetByList(List<int> listTwo, HashSet<int> uniqueList)
    {
        foreach (var number in listTwo)
        {
            uniqueList.Add(number);
        }
    }

}