How do you concatenate Lists in C#?

Question

If I have:

List myList1;
List myList2;

myList1 = getMeAList();
// Checked myList1, it contains 4 strings

myList2 = getMeAnother         


        

Answer 1

I know this is old but I came upon this post quickly thinking Concat would be my answer. Union worked great for me. Note, it returns only unique values but knowing that I was getting unique values anyway this solution worked for me.

namespace TestProject
{
    public partial class Form1 :Form
    {
        public Form1()
        {
            InitializeComponent();

            List FirstList = new List();
            FirstList.Add("1234");
            FirstList.Add("4567");

            // In my code, I know I would not have this here but I put it in as a demonstration that it will not be in the secondList twice
            FirstList.Add("Three");  

            List secondList = GetList(FirstList);            
            foreach (string item in secondList)
                Console.WriteLine(item);
        }

        private List GetList(List SortBy)
        {
            List list = new List();
            list.Add("One");
            list.Add("Two");
            list.Add("Three");

            list = list.Union(SortBy).ToList();

            return list;
        }
    }
}

The output is:

One
Two
Three
1234
4567