ComboBoxRenderer Klas

Definitie

public ref class ComboBoxRenderer sealed

public ref class ComboBoxRenderer abstract sealed

public sealed class ComboBoxRenderer

public static class ComboBoxRenderer

type ComboBoxRenderer = class

Public NotInheritable Class ComboBoxRenderer

Public Class ComboBoxRenderer

Overname

Object

ComboBoxRenderer

Voorbeelden

In het volgende codevoorbeeld ziet u hoe u een aangepast besturingselement maakt dat gebruikmaakt van de DrawTextBox en DrawDropDownButton methoden om een keuzelijst met invoervak te tekenen die reageert op muisklikken.

#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 ComboBoxRendererSample
{
    ref class CustomComboBox: public Control
    {
    private:
        System::Drawing::Size arrowSize;
        Rectangle arrowRectangle;
        Rectangle topTextBoxRectangle;
        Rectangle bottomTextBoxRectangle;
        ComboBoxState textBoxState;
        ComboBoxState arrowState;
        String^ bottomText;
        bool isActivated;
        int minHeight;
        int minWidth;

    public:
        CustomComboBox() : Control()

          {
              minHeight = 38;
              minWidth = 40; 
              this->Location = Point(10, 10);
              this->Size = System::Drawing::Size(140, 38);
              this->Font = SystemFonts::IconTitleFont;
              this->Text = "Click the button";
              textBoxState = ComboBoxState::Normal;
              bottomText = "Using ComboBoxRenderer";
              arrowState = ComboBoxState::Normal;

              // Initialize the rectangles to look like the standard combo
              // box control.
              arrowSize = System::Drawing::Size(18, 20);
              arrowRectangle = Rectangle(ClientRectangle.X +
                  ClientRectangle.Width - arrowSize.Width - 1,
                  ClientRectangle.Y + 1,
                  arrowSize.Width,
                  arrowSize.Height);
              topTextBoxRectangle = Rectangle(ClientRectangle.X,
                  ClientRectangle.Y,
                  ClientRectangle.Width,
                  arrowSize.Height + 2);
              bottomTextBoxRectangle = Rectangle(ClientRectangle.X,
                  ClientRectangle.Y + topTextBoxRectangle.Height,
                  ClientRectangle.Width,
                  topTextBoxRectangle.Height - 6);
          }

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

            if (!ComboBoxRenderer::IsSupported)
            {
                this->Parent->Text = "Visual Styles Disabled";
                return;
            }

            this->Parent->Text = "CustomComboBox Enabled";

            // Always draw the main text box and drop down arrow in their
            // current states
            ComboBoxRenderer::DrawTextBox(e->Graphics, topTextBoxRectangle,
                this->Text, this->Font, textBoxState);
            ComboBoxRenderer::DrawDropDownButton(e->Graphics, arrowRectangle,
                arrowState);

            // Only draw the bottom text box if the arrow has been clicked
            if (isActivated)
            {
                ComboBoxRenderer::DrawTextBox(e->Graphics,
                    bottomTextBoxRectangle, bottomText, this->Font,
                    textBoxState);
            }
        }

    protected:
        virtual void OnMouseDown(MouseEventArgs^ e) override 
        {
            Control::OnMouseDown(e);

            // Check whether the user clicked the arrow.
            if (arrowRectangle.Contains(e->Location) &&
                ComboBoxRenderer::IsSupported)
            {
                // Draw the arrow in the pressed state.
                arrowState = ComboBoxState::Pressed;

                // The user has activated the combo box.
                if (!isActivated)
                {
                    this->Text = "Clicked!";
                    textBoxState = ComboBoxState::Pressed;
                    isActivated = true;
                }

                // The user has deactivated the combo box.
                else
                {
                    this->Text = "Click here";
                    textBoxState = ComboBoxState::Normal;
                    isActivated = false;
                }

                // Redraw the control.
                Invalidate();
            }
        }

    protected:
        virtual void OnMouseUp(MouseEventArgs^ e) override 
        {
            Control::OnMouseUp(e);

            if (arrowRectangle.Contains(e->Location) &&
                ComboBoxRenderer::IsSupported)
            {
                arrowState = ComboBoxState::Normal;
                Invalidate();
            }
        }
    };

    ref class Form1 : public Form
    {
    public:
        Form1() : Form()
        {
            this->Size = System::Drawing::Size(300, 300);
            CustomComboBox^ ComboBox1 = gcnew CustomComboBox();
            Controls->Add(ComboBox1);
        }

    };

}

[STAThread]
int main()
{
    // The call to EnableVisualStyles below does not affect
    // whether ComboBoxRenderer.IsSupported is true; as long as visual
    // styles are enabled by the operating system, IsSupported is true.
    Application::EnableVisualStyles();
    Application::Run(gcnew ComboBoxRendererSample::Form1());

}

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

namespace ComboBoxRendererSample
{
    class Form1 : Form
    {
        public Form1()
            : base()
        {
            this.Size = new Size(300, 300);
            CustomComboBox ComboBox1 = new CustomComboBox();
            Controls.Add(ComboBox1);
        }

        [STAThread]
        static void Main()
        {
            // The call to EnableVisualStyles below does not affect
            // whether ComboBoxRenderer.IsSupported is true; as long as visual
            // styles are enabled by the operating system, IsSupported is true.
            Application.EnableVisualStyles();
            Application.Run(new Form1());
        }
    }

    public class CustomComboBox : Control
    {
        private Size arrowSize;
        private Rectangle arrowRectangle;
        private Rectangle topTextBoxRectangle;
        private Rectangle bottomTextBoxRectangle;
        private ComboBoxState textBoxState = ComboBoxState.Normal;
        private ComboBoxState arrowState = ComboBoxState.Normal;
        private String bottomText = "Using ComboBoxRenderer";
        private bool isActivated = false;
        private const int minHeight = 38;
        private const int minWidth = 40;

        public CustomComboBox()
            : base()
        {
            this.Location = new Point(10, 10);
            this.Size = new Size(140, 38);
            this.Font = SystemFonts.IconTitleFont;
            this.Text = "Click the button";

            // Initialize the rectangles to look like the standard combo 
            // box control.
            arrowSize = new Size(18, 20);
            arrowRectangle = new Rectangle(ClientRectangle.X +
                ClientRectangle.Width - arrowSize.Width - 1,
                ClientRectangle.Y + 1,
                arrowSize.Width,
                arrowSize.Height);
            topTextBoxRectangle = new Rectangle(ClientRectangle.X,
                ClientRectangle.Y,
                ClientRectangle.Width,
                arrowSize.Height + 2);
            bottomTextBoxRectangle = new Rectangle(ClientRectangle.X,
                ClientRectangle.Y + topTextBoxRectangle.Height,
                ClientRectangle.Width,
                topTextBoxRectangle.Height - 6);
        }

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

            if (!ComboBoxRenderer.IsSupported)
            {
                this.Parent.Text = "Visual Styles Disabled";
                return;
            }

            this.Parent.Text = "CustomComboBox Enabled";

            // Always draw the main text box and drop down arrow in their 
            // current states
            ComboBoxRenderer.DrawTextBox(e.Graphics, topTextBoxRectangle,
                this.Text, this.Font, textBoxState);
            ComboBoxRenderer.DrawDropDownButton(e.Graphics, arrowRectangle,
                arrowState);

            // Only draw the bottom text box if the arrow has been clicked
            if (isActivated)
            {
                ComboBoxRenderer.DrawTextBox(e.Graphics,
                    bottomTextBoxRectangle, bottomText, this.Font,
                    textBoxState);
            }
        }

        protected override void OnMouseDown(MouseEventArgs e)
        {
            base.OnMouseDown(e);

            // Check whether the user clicked the arrow.
            if (arrowRectangle.Contains(e.Location) &&
                ComboBoxRenderer.IsSupported)
            {
                // Draw the arrow in the pressed state.
                arrowState = ComboBoxState.Pressed;

                // The user has activated the combo box.
                if (!isActivated)
                {
                    this.Text = "Clicked!";
                    textBoxState = ComboBoxState.Pressed;
                    isActivated = true;
                }

                // The user has deactivated the combo box.
                else
                {
                    this.Text = "Click here";
                    textBoxState = ComboBoxState.Normal;
                    isActivated = false;
                }

                // Redraw the control.
                Invalidate();
            }
        }

        protected override void OnMouseUp(MouseEventArgs e)
        {
            base.OnMouseUp(e);

            if (arrowRectangle.Contains(e.Location) &&
                ComboBoxRenderer.IsSupported)
            {
                arrowState = ComboBoxState.Normal;
                Invalidate();
            }
        }
    }
}

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

Namespace ComboBoxRendererSample
    Class Form1
        Inherits Form

        Public Sub New()
            Me.Size = New Size(300, 300)
            Dim ComboBox1 As New CustomComboBox()
            Controls.Add(ComboBox1)
        End Sub

        <STAThread()> _
        Shared Sub Main()
            ' The call to EnableVisualStyles below does not affect
            ' whether ComboBoxRenderer.IsSupported is true; as long as visual
            ' styles are enabled by the operating system, IsSupported is true.
            Application.EnableVisualStyles()
            Application.Run(New Form1())
        End Sub
    End Class

    Public Class CustomComboBox
        Inherits Control

        Private arrowSize As Size
        Private arrowRectangle As Rectangle
        Private topTextBoxRectangle As Rectangle
        Private bottomTextBoxRectangle As Rectangle
        Private textBoxState As ComboBoxState = ComboBoxState.Normal
        Private arrowState As ComboBoxState = ComboBoxState.Normal
        Private bottomText As String = "Using ComboBoxRenderer"
        Private isActivated As Boolean = False
        Private minHeight As Integer = 38
        Private minWidth As Integer = 40

        Public Sub New()
            Me.Location = New Point(10, 10)
            Me.Size = New Size(140, 38)
            Me.Font = SystemFonts.IconTitleFont
            Me.Text = "Click the button"

            ' Initialize the rectangles to look like the standard combo 
            ' box control.
            arrowSize = New Size(18, 20)
            arrowRectangle = New Rectangle(Me.ClientRectangle.X + _
                Me.ClientRectangle.Width - arrowSize.Width - 1, _
                Me.ClientRectangle.Y + 1, arrowSize.Width, _
                arrowSize.Height)
            topTextBoxRectangle = New Rectangle(Me.ClientRectangle.X, _
                Me.ClientRectangle.Y, Me.ClientRectangle.Width, _
                arrowSize.Height + 2)
            bottomTextBoxRectangle = New Rectangle(Me.ClientRectangle.X, _
                Me.ClientRectangle.Y + topTextBoxRectangle.Height, _
                Me.ClientRectangle.Width, topTextBoxRectangle.Height - 6)
        End Sub

        ' Draw the combo box in the current state.
        Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs)
            MyBase.OnPaint(e)

            If Not ComboBoxRenderer.IsSupported Then
                Me.Parent.Text = "Visual Styles	Disabled"
                Return
            End If

            Me.Parent.Text = "CustomComboBox Enabled"

            ' Always draw the main text box and drop down arrow in their 
            ' current states.
            ComboBoxRenderer.DrawTextBox(e.Graphics, topTextBoxRectangle, _
                Me.Text, Me.Font, textBoxState)
            ComboBoxRenderer.DrawDropDownButton(e.Graphics, arrowRectangle, _
                arrowState)

            ' Only draw the bottom text box if the arrow has been clicked.
            If isActivated Then
                ComboBoxRenderer.DrawTextBox(e.Graphics, _
                    bottomTextBoxRectangle, bottomText, Me.Font, textBoxState)
            End If
        End Sub

        Protected Overrides Sub OnMouseDown(ByVal e As MouseEventArgs)
            MyBase.OnMouseDown(e)

            ' Check whether the user clicked the arrow.
            If arrowRectangle.Contains(e.Location) And _
                ComboBoxRenderer.IsSupported Then

                ' Draw the arrow in the pressed state.
                arrowState = ComboBoxState.Pressed

                ' The user has activated the combo box.
                If Not isActivated Then
                    Me.Text = "Clicked!"
                    textBoxState = ComboBoxState.Pressed
                    isActivated = True

                ' The user has deactivated the combo box.
                Else
                    Me.Text = "Click here"
                    textBoxState = ComboBoxState.Normal
                    isActivated = False
                End If

                ' Redraw the control.
                Invalidate()
            End If
        End Sub

        Protected Overrides Sub OnMouseUp(ByVal e As MouseEventArgs)
            MyBase.OnMouseUp(e)
            If arrowRectangle.Contains(e.Location) And _
                ComboBoxRenderer.IsSupported Then
                arrowState = ComboBoxState.Normal
                Invalidate()
            End If
        End Sub

    End Class
End Namespace

Opmerkingen

De ComboBoxRenderer klasse biedt een set static methoden die kunnen worden gebruikt om een besturingselement met invoervak weer te geven met de huidige visuele stijl van het besturingssysteem. Het weergeven van een besturingselement verwijst naar het tekenen van de gebruikersinterface van een besturingselement. Dit is handig als u een aangepast besturingselement tekent dat het uiterlijk van de huidige visuele stijl moet hebben. Als u een keuzelijst met invoervak wilt tekenen, gebruikt u de DrawTextBox methode om het tekstvak en de DrawDropDownButton methode te tekenen om de vervolgkeuzepijl te tekenen.

Als visuele stijlen zijn ingeschakeld in het besturingssysteem en visuele stijlen worden toegepast op het clientgebied van toepassingsvensters en DrawTextBoxDrawDropDownButton wordt de keuzelijst met invoervak met de huidige visuele stijl getekend. Anders zullen deze methoden een InvalidOperationException. Als u wilt bepalen of de leden van deze klasse kunnen worden gebruikt, kunt u de waarde van de IsSupported eigenschap controleren.

Deze klasse verpakt de functionaliteit van een System.Windows.Forms.VisualStyles.VisualStyleRenderer die is ingesteld op een van de elementen die worden weergegeven door de klassen System.Windows.Forms.VisualStyles.VisualStyleElement.ComboBox.DropDownButton en System.Windows.Forms.VisualStyles.VisualStyleElement.TextBox.TextEdit. Zie Weergavebesturingselementen met visuele stijlen voor meer informatie.

Zie ook

• VisualStyleRenderer
• VisualStyleElement