Checkbox in C#

CheckBox is a control that allows the user to make single or multiple selections from a list of options. In C#, CheckBox class from System.Windows.Forms namespace is used to work with checkbox control. It is a part of Windows Forms and is used to take input from the user. It can also be used to select from the options such as true/false or yes/no.

A user can click on a checkbox to select the associated item and can click on it again to deselect the item. It can be used along with an image or text or both.

Types of Checkbox

We can create checkbox in two different ways:

1. Using Form Designer at design time.
2. Using CheckBox class in code at run time.

We can create checkBox at design time by dragging a checkbox control from the ToolBox and then dropping it on the windows form. Then, we can go to the properties of the checkbox control and can modify it.

To create a checkbox at runtime, we need to use the CheckBox class.

Syntax: 

CheckBox check_box = new CheckBox();

After this, we can set the properties of the checkbox according to our requirements.

//setting location of checkbox
check_box.Location = new Point(300,150);
//setting height and width for checkbox
check_box.Height = 50;
check_box.Width = 50;
//setting text for checkbox
check_box.Text = “Yes”;

At last, we need to add this checkbox to the Windows Form by using:

this.Controls.Add(check_box);

CheckBox Properties

C# provides many properties for the checkbox.

Property	Description
AllowDrop	It is used to get or set a value that determines whether the checkbox control can accept data that a user drags onto it.
Appearance	It is used to get or set a value that determines the appearance of the checkbox control.
AutoCheck	It is used to get or set a value that determines whether the values of the Checked or CheckState properties or the appearance of the checkbox are automatically changed when the checkbox is clicked.
AutoSize	It is used to get or set a value that determines whether the checkbox control resizes based on its content.
BackColor	It is used to get or set the background color of the checkbox control.
BackGroundImage	It is used to get or set the background image displayed in the checkbox control.
CanFocus	It is used to get a value that determines whether the checkbox control can receive focus.
Checked	It is used to get or set a value that determines whether the checkbox control is in the checked state.
CheckState	It is used to get or set the state of the checkbox.
DefaultSize	It is used to get the default size of the checkbox control.
Enabled	It is used to get or set a value that determines whether the checkbox control can respond to user interaction.
Focused	It is used to get a value that determines whether the checkbox control has input focus.
Font	It is used to get or set the font of text displayed by the checkbox control.
ForeColor	It is used to get or set the foreground color of the checkbox control.
Height	It is used to get or set the height of the checkbox control.
Image	It is used to get or set the image which is displayed on the checkbox control.
Location	It is used to get or set the coordinates of the upper left corner of the control relative to the upper left corner of its parent container.
Margin	It is used to get or set the space between controls.
Name	It is used to get or set the name of the checkbox control.
Size	It is used to get or set the height and width of the checkbox control.
Text	It is used to get or set the text associated with the checkbox control.
ThreeState	It is used to get or set a value that determines whether the checkbox will allow three check states instead of two.
Width	It is used to get or set the width of the checkbox control.

CheckBox Events

Let us see some important events for the CheckBox provided by C#:

Event	Description
CheckedChanged	This event occurs when the value of Checked property changes.
CheckStateChanged	This event occurs when the value of CheckState property changes.
Click	This event occurs when the checkbox is clicked.
GotFocus	This event occurs when the checkbox receives focus.
Leave	This event occurs when the input focus leaves the checkbox.
LostFocus	This event occurs when the checkbox loses focus.
MouseClick	This event occurs when the checkbox is clicked by the mouse.
MouseDoubleClick	This event occurs when the checkbox is double-clicked by a mouse.
TextChanged	This event occurs when the value of Text property changes.

Implementation of CheckBox in C#

Below is an example of how to implement the checkbox in c #

Example:

Code:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace WindowsFormsApp1
{
public partial class CheckBoxDemo : Form
{
public CheckBoxDemo()
{
InitializeComponent();
}
private void CheckBoxDemo_Load(object sender, EventArgs e)
{
//Creating and setting properties of Label
Label label = new Label();
label.Text = "Select your technical skills";
label.AutoSize = true;
label.Location = new Point(192, 77);
label.Font = new Font("Microsoft Sans Serif", 11);
//Adding label to form
this.Controls.Add(label);
//Creating and setting properties of CheckBox
CheckBox checkbox1 = new CheckBox();
checkbox1.Location = new Point(195, 111);
checkbox1.Text = "C";
//Adding checkbox to form
this.Controls.Add(checkbox1);
CheckBox checkbox2 = new CheckBox();
checkbox2.Location = new Point(195, 156);
checkbox2.Text = "C++";
this.Controls.Add(checkbox2);
CheckBox checkbox3 = new CheckBox();
checkbox3.Location = new Point(195, 195);
checkbox3.Text = "C#";
this.Controls.Add(checkbox3);
CheckBox checkbox4 = new CheckBox();
checkbox4.Location = new Point(195, 235);
checkbox4.Text = "JAVA";
this.Controls.Add(checkbox4);
CheckBox checkbox5 = new CheckBox();
checkbox5.Location = new Point(195, 275);
checkbox5.Text = "HTML";
this.Controls.Add(checkbox5);
}
}
}

Output:

Conclusion – Checkbox in C#

A checkbox in C# can also have an indeterminate state. This can be achieved by setting the CheckState property to ‘Indeterminate. It is a state between ‘Yes’ and ‘No’ in which the checkbox will neither be checked nor unchecked.

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