CheckBoxRenderer Class

Definition

Namespace:

System.Windows.Forms

Assembly:

System.Windows.Forms.dll

Source:

CheckBoxRenderer.cs

Provides methods used to render a check box control with or without visual styles. This class cannot be inherited.

public ref class CheckBoxRenderer abstract sealed

public static class CheckBoxRenderer

type CheckBoxRenderer = class

Public Class CheckBoxRenderer

Inheritance

Object

CheckBoxRenderer

Examples

The following code example demonstrates how to write a custom control that uses the DrawCheckBox method to draw a check box that responds to mouse clicks.

#using <System.dll>
#using <System.Drawing.dll>
#using <System.Windows.Forms.dll>

using namespace System;
using namespace System::Drawing;
using namespace System::Windows::Forms;
using namespace System::Windows::Forms::VisualStyles;

namespace CheckBoxRendererSample
{
    ref class CustomCheckBox : Control
    {
        private:
        Rectangle textRectangleValue;
        Point clickedLocationValue;
        bool clicked;
        CheckBoxState state;

        public :
        CustomCheckBox() : Control()
        {
            this->textRectangleValue = Rectangle();
            this->clickedLocationValue = Point();
            this->clicked = false;
            this->state = CheckBoxState::UncheckedNormal;
            this->Location = Point(50, 50);
            this->Size = System::Drawing::Size(100, 20);
            this->Text = "Click here";
            this->Font = SystemFonts::IconTitleFont;
        }

        // Calculate the text bounds, exluding the check box.
        Rectangle getTextRectangle()
        {
            Graphics ^g = this->CreateGraphics();
            textRectangleValue.X = ClientRectangle.X +
                        CheckBoxRenderer::GetGlyphSize(g,
                        CheckBoxState::UncheckedNormal).Width;
            textRectangleValue.Y = ClientRectangle.Y;
            textRectangleValue.Width = ClientRectangle.Width -
                        CheckBoxRenderer::GetGlyphSize(g,
                        CheckBoxState::UncheckedNormal).Width;
            textRectangleValue.Height = ClientRectangle.Height;

            delete g;
            return textRectangleValue;
        }

protected:
        // Draw the check box in the current state.
        virtual void OnPaint(PaintEventArgs ^e) override
        {
            Control::OnPaint(e);

            CheckBoxRenderer::DrawCheckBox(e->Graphics,
                ClientRectangle.Location, this->getTextRectangle(), this->Text,
                this->Font, TextFormatFlags::HorizontalCenter,
                clicked, state);
        }


        // Draw the check box in the checked or unchecked state, alternately.
        virtual void OnMouseDown(MouseEventArgs ^e) override
        {
            Control::OnMouseDown(e);

            if (!clicked)
            {
                clicked = true;
                this->Text = "Clicked!";
                state = CheckBoxState::CheckedPressed;
                Invalidate();
            }
            else
            {
                clicked = false;
                this->Text = "Click here";
                state = CheckBoxState::UncheckedNormal;
                Invalidate();
            }
        }

        // Draw the check box in the hot state. 
        virtual void OnMouseHover(EventArgs ^e) override
        {
            Control::OnMouseHover(e);
            state = clicked ? CheckBoxState::CheckedHot :
                CheckBoxState::UncheckedHot;
            Invalidate();
        }

        // Draw the check box in the hot state. 
        virtual void OnMouseUp(MouseEventArgs ^e) override
        {
            Control::OnMouseUp(e);
            this->OnMouseHover(e);
        }

        // Draw the check box in the unpressed state.
        virtual void OnMouseLeave(EventArgs ^e) override
        {
            Control::OnMouseLeave(e);
            state = clicked ? CheckBoxState::CheckedNormal :
                CheckBoxState::UncheckedNormal;
            Invalidate();
        } 
    }; 

    ref class Form1: public Form
    {
    public:
        Form1() : Form() 
        {
            CustomCheckBox ^CheckBox1 = gcnew CustomCheckBox();
            Controls->Add(CheckBox1);

            if (Application::RenderWithVisualStyles) 
            {
                this->Text = "Visual Styles Enabled";
            }
            else 
            {
                this->Text = "Visual Styles Disabled";
            }
        }
    };
}


[STAThread]
int main()
{
    // If you do not call EnableVisualStyles below, then 
    // CheckBoxRenderer.DrawCheckBox automatically detects 
    // this and draws the check box without visual styles.
    Application::EnableVisualStyles();
    Application::Run(gcnew CheckBoxRendererSample::Form1());
}

using System;
using System.Drawing;
using System.Windows.Forms;
using System.Windows.Forms.VisualStyles;

namespace CheckBoxRendererSample
{
    class Form1 : Form
    {
        public Form1()
            : base()
        {
            CustomCheckBox CheckBox1 = new CustomCheckBox();
            Controls.Add(CheckBox1);

            if (Application.RenderWithVisualStyles)
                this.Text = "Visual Styles Enabled";
            else
                this.Text = "Visual Styles Disabled";
        }

        [STAThread]
        static void Main()
        {
            // If you do not call EnableVisualStyles below, then 
            // CheckBoxRenderer.DrawCheckBox automatically detects 
            // this and draws the check box without visual styles.
            Application.EnableVisualStyles();
            Application.Run(new Form1());
        }
    }

    public class CustomCheckBox : Control
    {
        private Rectangle textRectangleValue = new Rectangle();
        private Point clickedLocationValue = new Point();
        private bool clicked = false;
        private CheckBoxState state = CheckBoxState.UncheckedNormal;

        public CustomCheckBox()
            : base()
        {
            this.Location = new Point(50, 50);
            this.Size = new Size(100, 20);
            this.Text = "Click here";
            this.Font = SystemFonts.IconTitleFont;
        }

        // Calculate the text bounds, exluding the check box.
        public Rectangle TextRectangle
        {
            get
            {
                using (Graphics g = this.CreateGraphics())
                {
                    textRectangleValue.X = ClientRectangle.X +
                        CheckBoxRenderer.GetGlyphSize(g,
                        CheckBoxState.UncheckedNormal).Width;
                    textRectangleValue.Y = ClientRectangle.Y;
                    textRectangleValue.Width = ClientRectangle.Width -
                        CheckBoxRenderer.GetGlyphSize(g,
                        CheckBoxState.UncheckedNormal).Width;
                    textRectangleValue.Height = ClientRectangle.Height;
                }

                return textRectangleValue;
            }
        }

        // Draw the check box in the current state.
        protected override void OnPaint(PaintEventArgs e)
        {
            base.OnPaint(e);

            CheckBoxRenderer.DrawCheckBox(e.Graphics,
                ClientRectangle.Location, TextRectangle, this.Text,
                this.Font, TextFormatFlags.HorizontalCenter,
                clicked, state);
        }

        // Draw the check box in the checked or unchecked state, alternately.
        protected override void OnMouseDown(MouseEventArgs e)
        {
            base.OnMouseDown(e);

            if (!clicked)
            {
                clicked = true;
                this.Text = "Clicked!";
                state = CheckBoxState.CheckedPressed;
                Invalidate();
            }
            else
            {
                clicked = false;
                this.Text = "Click here";
                state = CheckBoxState.UncheckedNormal;
                Invalidate();
            }
        }

        // Draw the check box in the hot state. 
        protected override void OnMouseHover(EventArgs e)
        {
            base.OnMouseHover(e);
            state = clicked ? CheckBoxState.CheckedHot :
                CheckBoxState.UncheckedHot;
            Invalidate();
        }

        // Draw the check box in the hot state. 
        protected override void OnMouseUp(MouseEventArgs e)
        {
            base.OnMouseUp(e);
            this.OnMouseHover(e);
        }

        // Draw the check box in the unpressed state.
        protected override void OnMouseLeave(EventArgs e)
        {
            base.OnMouseLeave(e);
            state = clicked ? CheckBoxState.CheckedNormal :
                CheckBoxState.UncheckedNormal;
            Invalidate();
        }
    }
}

Imports System.Drawing
Imports System.Windows.Forms
Imports System.Windows.Forms.VisualStyles

Namespace CheckBoxRendererSample

    Class Form1
        Inherits Form

        Public Sub New()
            Dim CheckBox1 As New CustomCheckBox()
            Controls.Add(CheckBox1)

            If Application.RenderWithVisualStyles Then
                Me.Text = "Visual Styles Enabled"
            Else
                Me.Text = "Visual Styles Disabled"
            End If
        End Sub

        <STAThread()> _
        Shared Sub Main()
            ' If you do not call EnableVisualStyles below, then 
            ' CheckBoxRenderer.DrawCheckBox automatically detects   
            ' this and draws the check box without visual styles.
            Application.EnableVisualStyles()
            Application.Run(New Form1())
        End Sub
    End Class

    Public Class CustomCheckBox
        Inherits Control

        Private textRectangleValue As New Rectangle()
        Private clickedLocationValue As New Point()
        Private clicked As Boolean = False
        Private state As CheckBoxState = CheckBoxState.UncheckedNormal

        Public Sub New()
            With Me
                .Location = New Point(50, 50)
                .Size = New Size(100, 20)
                .Text = "Click here"
                .Font = SystemFonts.IconTitleFont
            End With
        End Sub

        ' Calculate the text bounds, exluding the check box.
        Public ReadOnly Property TextRectangle() As Rectangle
            Get
                Using g As Graphics = Me.CreateGraphics()
                    With textRectangleValue
                        .X = Me.ClientRectangle.X + _
                            CheckBoxRenderer.GetGlyphSize(g, _
                            CheckBoxState.UncheckedNormal).Width
                        .Y = Me.ClientRectangle.Y
                        .Width = Me.ClientRectangle.Width - _
                            CheckBoxRenderer.GetGlyphSize(g, _
                            CheckBoxState.UncheckedNormal).Width
                        .Height = Me.ClientRectangle.Height
                    End With
                End Using
                Return textRectangleValue
            End Get
        End Property

        ' Draw the check box in the current state.
        Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs)
            MyBase.OnPaint(e)
            CheckBoxRenderer.DrawCheckBox(e.Graphics, _
                Me.ClientRectangle.Location, TextRectangle, Me.Text, _
                Me.Font, TextFormatFlags.HorizontalCenter, _
                clicked, state)
        End Sub

        ' Draw the check box in the checked or unchecked state, alternately.
        Protected Overrides Sub OnMouseDown(ByVal e As MouseEventArgs)
            MyBase.OnMouseDown(e)
            If Not clicked Then
                With Me
                    .clicked = True
                    .Text = "Clicked!"
                    .state = CheckBoxState.CheckedPressed
                End With
                Invalidate()
            Else
                With Me
                    .clicked = False
                    .Text = "Click here"
                    .state = CheckBoxState.UncheckedNormal
                End With
                Invalidate()
            End If
        End Sub

        ' Draw the check box in the hot state. 
        Protected Overrides Sub OnMouseHover(ByVal e As EventArgs)
            MyBase.OnMouseHover(e)
            If clicked Then
                state = CheckBoxState.CheckedHot
            Else
                state = CheckBoxState.UncheckedHot
            End If
            Invalidate()
        End Sub

        ' Draw the check box in the hot state. 
        Protected Overrides Sub OnMouseUp(ByVal e As MouseEventArgs)
            MyBase.OnMouseUp(e)
            Me.OnMouseHover(e)
        End Sub

        ' Draw the check box in the unpressed state.
        Protected Overrides Sub OnMouseLeave(ByVal e As EventArgs)
            MyBase.OnMouseLeave(e)
            If clicked Then
                state = CheckBoxState.CheckedNormal
            Else
                state = CheckBoxState.UncheckedNormal
            End If
            Invalidate()
        End Sub

    End Class
End Namespace

Remarks

The CheckBoxRenderer class provides a set of static methods that can be used to render a check box control. Rendering a control refers to drawing the user interface of a control. To draw a check box, use one of the DrawCheckBox methods. These methods provide a variety of options, such as drawing text or an image with the check box.

If visual styles are enabled in the operating system and visual styles are applied to the current application, DrawCheckBox will draw the check box with the current visual style. Otherwise, DrawCheckBox will draw the check box with the classic Windows style. This is useful if you are drawing a custom control that should automatically match the current visual style setting of the operating system.

This class wraps the functionality of a System.Windows.Forms.VisualStyles.VisualStyleRenderer that is set to one of the elements exposed by the System.Windows.Forms.VisualStyles.VisualStyleElement.Button.CheckBox class. For more information, see Rendering Controls with Visual Styles.

Properties

RenderMatchingApplicationState

Gets or sets a value indicating whether the renderer uses the application state to determine rendering style.

Methods

DrawCheckBox(Graphics, Point, CheckBoxState)	Draws a check box control in the specified state and location.
DrawCheckBox(Graphics, Point, Rectangle, String, Font, Boolean, CheckBoxState)	Draws a check box control in the specified state and location, with the specified text, and with an optional focus rectangle.
DrawCheckBox(Graphics, Point, Rectangle, String, Font, Image, Rectangle, Boolean, CheckBoxState)	Draws a check box control in the specified state and location, with the specified text and image, and with an optional focus rectangle.
DrawCheckBox(Graphics, Point, Rectangle, String, Font, TextFormatFlags, Boolean, CheckBoxState)	Draws a check box control in the specified state and location, with the specified text and text formatting, and with an optional focus rectangle.
DrawCheckBox(Graphics, Point, Rectangle, String, Font, TextFormatFlags, Image, Rectangle, Boolean, CheckBoxState)	Draws a check box control in the specified state and location; with the specified text, text formatting, and image; and with an optional focus rectangle.
DrawParentBackground(Graphics, Rectangle, Control)	Draws the background of a control's parent in the specified area.
GetGlyphSize(Graphics, CheckBoxState)	Returns the size of the check box glyph.
IsBackgroundPartiallyTransparent(CheckBoxState)	Indicates whether the background of the check box has semitransparent or alpha-blended pieces.

See also

• EnableVisualStyles()
• RenderWithVisualStyles
• VisualStyleRenderer
• VisualStyleElement