[c#] How do I group Windows Form radio buttons?

How can I group the radio buttons in Windows Form application (a lot like ASP.NET's radiobuttonlist!)?

So I can switch between each case chosen from the options.

GroupBox is better.But not only group box, even you can use Panels (System.Windows.Forms.Panel).

• That is very usefully when you are designing Internet Protocol version 4 setting dialog.(Check it with your pc(windows),then you can understand the behavior)

If you cannot put them into one container, then you have to write code to change checked state of each RadioButton:

private void rbDataSourceFile_CheckedChanged(object sender, EventArgs e)
{
    rbDataSourceNet.Checked = !rbDataSourceFile.Checked;
}

private void rbDataSourceNet_CheckedChanged(object sender, EventArgs e)
{
  rbDataSourceFile.Checked = !rbDataSourceNet.Checked;
}

Radio button without panel

public class RadioButton2 : RadioButton
{
   public string GroupName { get; set; }
}

private void RadioButton2_Clicked(object sender, EventArgs e)
{
    RadioButton2 rb = (sender as RadioButton2);

    if (!rb.Checked)
    {
       foreach (var c in Controls)
       {
           if (c is RadioButton2 && (c as RadioButton2).GroupName == rb.GroupName)
           {
              (c as RadioButton2).Checked = false;
           }
       }

       rb.Checked = true;
    }
}

private void Form1_Load(object sender, EventArgs e)
{
    //a group
    RadioButton2 rb1 = new RadioButton2();
    rb1.Text = "radio1";
    rb1.AutoSize = true;
    rb1.AutoCheck = false;
    rb1.Top = 50;
    rb1.Left = 50;
    rb1.GroupName = "a";
    rb1.Click += RadioButton2_Clicked;
    Controls.Add(rb1);

    RadioButton2 rb2 = new RadioButton2();
    rb2.Text = "radio2";
    rb2.AutoSize = true;
    rb2.AutoCheck = false;
    rb2.Top = 50;
    rb2.Left = 100;
    rb2.GroupName = "a";
    rb2.Click += RadioButton2_Clicked;
    Controls.Add(rb2);

    //b group
    RadioButton2 rb3 = new RadioButton2();
    rb3.Text = "radio3";
    rb3.AutoSize = true;
    rb3.AutoCheck = false;
    rb3.Top = 80;
    rb3.Left = 50;
    rb3.GroupName = "b";
    rb3.Click += RadioButton2_Clicked;
    Controls.Add(rb3);

    RadioButton2 rb4 = new RadioButton2();
    rb4.Text = "radio4";
    rb4.AutoSize = true;
    rb4.AutoCheck = false;
    rb4.Top = 80;
    rb4.Left = 100;
    rb4.GroupName = "b";
    rb4.Click += RadioButton2_Clicked;
    Controls.Add(rb4);
}

Put radio buttons inside GroupBox (or other panel)

Look at placing your radio buttons in a GroupBox.

I like the concept of grouping RadioButtons in WPF. There is a property GroupName that specifies which RadioButton controls are mutually exclusive (http://msdn.microsoft.com/de-de/library/system.windows.controls.radiobutton.aspx).

So I wrote a derived class for WinForms that supports this feature:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Diagnostics;
using System.Windows.Forms.VisualStyles;
using System.Drawing;
using System.ComponentModel;

namespace Use.your.own
{
    public class AdvancedRadioButton : CheckBox
    {
        public enum Level { Parent, Form };

        [Category("AdvancedRadioButton"),
        Description("Gets or sets the level that specifies which RadioButton controls are affected."),
        DefaultValue(Level.Parent)]
        public Level GroupNameLevel { get; set; }

        [Category("AdvancedRadioButton"),
        Description("Gets or sets the name that specifies which RadioButton controls are mutually exclusive.")]
        public string GroupName { get; set; }

        protected override void OnCheckedChanged(EventArgs e)
        {
            base.OnCheckedChanged(e);

            if (Checked)
            {
                var arbControls = (dynamic)null;
                switch (GroupNameLevel)
                {
                    case Level.Parent:
                        if (this.Parent != null)
                            arbControls = GetAll(this.Parent, typeof(AdvancedRadioButton));
                        break;
                    case Level.Form:
                        Form form = this.FindForm();
                        if (form != null)
                            arbControls = GetAll(this.FindForm(), typeof(AdvancedRadioButton));
                        break;
                }
                if (arbControls != null)
                    foreach (Control control in arbControls)
                        if (control != this &&
                            (control as AdvancedRadioButton).GroupName == this.GroupName)
                            (control as AdvancedRadioButton).Checked = false;
            }
        }

        protected override void OnClick(EventArgs e)
        {
            if (!Checked)
                base.OnClick(e);
        }

        protected override void OnPaint(PaintEventArgs pevent)
        {
            CheckBoxRenderer.DrawParentBackground(pevent.Graphics, pevent.ClipRectangle, this);

            RadioButtonState radioButtonState;
            if (Checked)
            {
                radioButtonState = RadioButtonState.CheckedNormal;
                if (Focused)
                    radioButtonState = RadioButtonState.CheckedHot;
                if (!Enabled)
                    radioButtonState = RadioButtonState.CheckedDisabled;
            }
            else
            {
                radioButtonState = RadioButtonState.UncheckedNormal;
                if (Focused)
                    radioButtonState = RadioButtonState.UncheckedHot;
                if (!Enabled)
                    radioButtonState = RadioButtonState.UncheckedDisabled;
            }

            Size glyphSize = RadioButtonRenderer.GetGlyphSize(pevent.Graphics, radioButtonState);
            Rectangle rect = pevent.ClipRectangle;
            rect.Width -= glyphSize.Width;
            rect.Location = new Point(rect.Left + glyphSize.Width, rect.Top);

            RadioButtonRenderer.DrawRadioButton(pevent.Graphics, new System.Drawing.Point(0, rect.Height / 2 - glyphSize.Height / 2), rect, this.Text, this.Font, this.Focused, radioButtonState);
        }

        private IEnumerable<Control> GetAll(Control control, Type type)
        {
            var controls = control.Controls.Cast<Control>();

            return controls.SelectMany(ctrl => GetAll(ctrl, type))
                                      .Concat(controls)
                                      .Where(c => c.GetType() == type);
        }
    }
}

You should place all the radio buttons of the group inside the same container such as a GroupBox or Panel.

All radio buttons inside of a share container are in the same group by default. Means, if you check one of them - others will be unchecked. If you want to create independent groups of radio buttons, you must situate them into different containers such as Group Box, or control their Checked state through code behind.