ComboBox Part 1 - adding items to the combobox

The ComboBox object provides the same benefits as a list does but it has the ability to expand and contract saving a lot of space in your windows form application.


In the next Quick Example, I'll show you how to add a ComboBox to a Windows Form Application and how to add items in it in two different ways.


1- By passing a range of items (in a list)
2- Adding a specific item by clicking a Button.

1. First, create a Windows Form Application Project

    2. Drag a ComboBox Object to your Window.

    3. Add some code:

     
     I created a List items to store some strings that will then be added at the Load event.
  List<string> items = new List<string>() { "1-Lucia", "2-Mauricio","3-Frank","4-Dog" };

   4. At the Load Event type this line.

    comboBox1.Items.AddRange(items.ToArray());

 5.Then I added a button to show another way of adding items to the combobox

 In the Button Event put this line:

 comboBox1.Items.Add(comboBox1.Items.Count+1+"-Item Added by Button");

FINISHED.

The full Code below (it is all commented)

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Windows.Forms;

namespace ComboBoxTest

{

    public partial class Form1 : Form

    {

        //creates and initialize a list with strings

        //(could contain any type of object)

        List<string> items = new List<string>() { "1-Lucia", "2-Mauricio", "3-Frank", "4-Dog" };

       

        public Form1()

        {

            InitializeComponent();

        }//constructor

        //The action takes part in the Load event, it could be a button or any other event.

        private void Form1_Load(object sender, EventArgs e)

        {

            //here we load the combobox with the list

            comboBox1.Items.AddRange(items.ToArray());

            //we set the selected to "1-Lucia", it also work with any kind of objects.(it depends on

            //what you put in the list.

            comboBox1.SelectedItem = "1-Lucia";

        }

        private void button_add_Click(object sender, EventArgs e)

        {

            //here we add an item to the combobox manually

            //"comboBox1.Items.Count+1" is just to show the apropiate index in the list

            //it calculates how many items are in the combobox and increments the value by 1

            comboBox1.Items.Add(comboBox1.Items.Count+1+"-Item Added by Button");

        }

      

    }

}

Screenshots:

At this point the ComboBox contains the List.

 

After the add button was clicked. The combobox contains now a new item.

Part 2 will cover the remove method and other combobox specific properties.


See you in the next C# Quick Example.