C# Add Multiple Items to List

How to Add Multiple Items to a List in C#

In this tutorial, you will learn how to add multiple items to a list in C#.

To add an item to a list, we use the List<T>.Add() method. To add multiple items, we use List.AddRange() method.

Learn more:

For example, suppose you have a list of strings like the following:

List<string> list = new List<string>() {"Apple", "Orange", "Kiwi", "Melon"};

If you want to add the text strings "Mango" and "Watermelon" to the above list, you would write the following:

list.Add("Mango");
list.Add("Watermelon");

The following is a sample program:

using System;
using System.Collections.Generic;
namespace Example
{
    public class Program
    {
        public static void Main(string[] args)
        {
            List<string> list = new List<string>()
            {
                "Apple", "Orange", "Kiwi", "Melon"
            };
            list.Add("Mango");
            list.Add("Watermelon");
 
            foreach (string item in list)
            {
                Console.WriteLine("Item: {0}", item);
            }
        }
    }
}

Output:

Item: Apple
Item: Orange
Item: Kiwi
Item: Melon
Item: Mango
Item: Watermelon

The List<T>.Add() method can only add one item at a time, so if you want to add multiple items at once, you need to use the List<T>.AddRange() method.

The syntax of the List<T>.AddRange() method is as follows:

List<T>.AddRange(IEnumerable<T> collection)

Let's take a look at the examples below:

The following sample program adds an array "str" of text strings with three elements to a list "list" with two elements:

using System;
using System.Collections.Generic;
namespace Example
{
    public class Program
    {
        public static void Main(string[] args)
        {
            string[] str = new string[3] { "Item 3", "Item 4", "Item 5" };
 
            List<string> list = new List<string>()
            {
                "Item 1", "Item 2"
            };
 
            list.AddRange(str);
            foreach (string item in list)
            {
                Console.WriteLine("Item: {0}", item);
            }
        }
    }
}

Output:

Item: Item 1
Item: Item 2
Item: Item 3
Item: Item 4
Item: Item 5

The following program adds the list of numbers "list1" to another list "list2":

using System;
using System.Collections.Generic;
namespace Example
{
    class Program
    {
        static void Main(string[] args)
        {
            List<int> list1 = new List<int>()
            {
                3, 4, 5
            };
 
            List<int> list2 = new List<int>()
            {
                1, 2
            };
 
            list2.AddRange(list1);
            foreach (int item in list2)
            {
                Console.WriteLine("Item: {0}", item);
            }
        }
    }
}

Output:

Item: 1
Item: 2
Item: 3
Item: 4
Item: 5

You can also loop through the list and add its items to a specified list.

The following sample code shows how to loop through a list and add its items to another list:

using System;
using System.Collections.Generic;
 
namespace Example
{
    public class Program
    {
        public static void Main(string[] args)
        {
            List<string> list1 = new List<string>()
            {
                "Item 3", "Item 4", "Item 5"
            };
 
            List<string> list2 = new List<string>()
            {
                "Item 1", "Item 2"
            };
            foreach (string item in list1)
            {
                list2.Add(item);
            }
            foreach (string item in list2)
            {
                Console.WriteLine("{0}", item);
            }
        }
    }
}

Output:

Item: Item 1
Item: Item 2
Item: Item 3
Item: Item 4
Item: Item 5

In this C# tutorial, we have discussed how to add multiple items to a list in C# programming.