RadioButton

This allows distinct selection of several items. In each group of RadioButtons, only one can be checked. Conceptually, this control implements an exclusive selection.

You should make a new Windows Forms application in Visual Studio. Then you can add GroupBox (or Panel) controls to it—these can contain RadioButtons.

Example program

Here we set the CheckedChanged handler on all Radiobuttons to the same event handler. It is possible for multiple controls to use the same event handler.

using System;
using System.Windows.Forms;

namespace WindowsFormsApplication11
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void radioButton1_CheckedChanged(object sender, EventArgs e)
        {
            // Executed when any radio button is changed.
            // ... It is wired up to every single radio button.
            // Search for first radio button in GroupBox.
            string result1 = null;
            foreach (Control control in this.groupBox1.Controls)
            {
                if (control is RadioButton)
                {
                    RadioButton radio = control as RadioButton;
                    if (radio.Checked)
                    {
                        result1 = radio.Text;
                    }
                }
            }
            // Search second GroupBox.
            string result2 = null;
            foreach (Control control in this.groupBox2.Controls)
            {
                if (control is RadioButton)
                {
                    RadioButton radio = control as RadioButton;
                    if (radio.Checked)
                    {
                        result2 = radio.Text;
                    }
                }
            }
            this.Text = result1 + " " + result2;
        }
    }
}

Groups

RadioButtons are grouped according to their enclosing control. To create multiple groups of RadioButtons, add containers such as Panel or GroupBox and then put RadioButtons inside.

RadioButton, CheckBox

So when should you use a RadioButton as opposed to a CheckBox? If only one option can be logically selected, then you should use a RadioButton.

The RadioButton control provides a user interface for an exclusive selection. We looked at how to use event handlers on RadioButtons.