CheckBox 是一個允許使用者從選項清單中進行單一或多個選擇的控制項。在 C# 中，System.Windows.Forms 命名空間中的 CheckBox 類別用於處理複選框控制項。它是 Windows 窗體的一部分，用於取得使用者的輸入。它也可用於從 true/false 或 yes/no 等選項中進行選擇。
使用者可以點擊複選框來選擇關聯的項目，並可以再次按一下它來取消選擇該項目。它可以與圖像或文字或兩者一起使用。
我們可以用兩種不同的方式來建立複選框：
我們可以在設計時建立複選框，方法是從工具箱中拖曳複選框控件，然後將其放在 Windows 窗體上。然後，我們可以進入複選框控制項的屬性並對其進行修改。
要在執行時建立複選框，我們需要使用 CheckBox 類別。
文法：
CheckBox check_box = new CheckBox();
之後，我們就可以依照自己的需求設定複選框的屬性了。
//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”;
最後，我們需要使用以下方法將此複選框新增至 Windows 窗體：
this.Controls.Add(check_box);
C# 為複選框提供了許多屬性。
| 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. |
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. |
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:
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.
以上是C# 中的複選框的詳細內容。更多資訊請關注PHP中文網其他相關文章！
