ProgressBarRenderer Class

Definition

Namespace:

System.Windows.Forms

Assembly:

System.Windows.Forms.dll

Provides methods used to render a progress bar control with visual styles. This class cannot be inherited.

public ref class ProgressBarRenderer abstract sealed

public static class ProgressBarRenderer

type ProgressBarRenderer = class

Public Class ProgressBarRenderer

Inheritance

Object

ProgressBarRenderer

Examples

The following code example demonstrates how to create a custom control that uses the DrawVerticalBar and DrawVerticalChunks methods to draw a vertical progress bar. The control uses a Timer to redraw the progress bar with an added piece each second. The SetupProgressBar method uses the ChunkThickness and ChunkSpaceThickness properties to calculate the height of each progressively larger rectangle that is drawn.

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

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

namespace ProgressBarRendererSample
{
    public ref class VerticalProgressBar : public Control
    {
    private:
        int numberChunksValue;
        int ticks;
        Timer^ progressTimer;
        array<Rectangle>^ progressBarRectangles;

    public:
        VerticalProgressBar() : Control()
        {
            this->Location = Point(10, 10);
            this->Width = 50;
            progressTimer = gcnew Timer();

            // The progress bar will update every second.
            progressTimer->Interval = 1000;
            progressTimer->Tick += gcnew EventHandler(this,
                &VerticalProgressBar::progressTimer_Tick);

            // This property also calls SetupProgressBar to initialize
            // the progress bar rectangles if styles are enabled.
            NumberChunks = 20;

            // Set the default height if visual styles are not enabled.
            if (!ProgressBarRenderer::IsSupported)
            {
                this->Height = 100;
            }
        }

        // Specify the number of progress bar chunks to base the height on.
    public:
        property int NumberChunks
        {
            int get()
            {
                return numberChunksValue;
            }

            void set(int value)
            {
                if (value <= 50 && value > 0)
                {
                    numberChunksValue = value;
                }
                else
                {
                    MessageBox::Show("Number of chunks must be between " +
                        "0 and 50; defaulting to 10");
                    numberChunksValue = 10;
                }

                // Recalculate the progress bar size, if visual styles
                // are active.
                if (ProgressBarRenderer::IsSupported)
                {
                    SetupProgressBar();
                }
            }
        }

        // Draw the progress bar in its normal state.
    protected:
        virtual void OnPaint(PaintEventArgs^ e) override
        {
            __super::OnPaint(e);

            if (ProgressBarRenderer::IsSupported)
            {
                ProgressBarRenderer::DrawVerticalBar(e->Graphics, 
                    ClientRectangle);
                this->Parent->Text = "VerticalProgressBar Enabled";
            }
            else
            {
                this->Parent->Text = "VerticalProgressBar Disabled";
            }
        }

        // Initialize the rectangles used to paint the states of the
        // progress bar.
    private:
        void SetupProgressBar()
        {
            if (!ProgressBarRenderer::IsSupported)
            {
                return;
            }

            // Determine the size of the progress bar frame.
            this->Size = System::Drawing::Size(ClientRectangle.Width,
                (NumberChunks * (ProgressBarRenderer::ChunkThickness + 
                (2 * ProgressBarRenderer::ChunkSpaceThickness))) + 6);

            // Initialize the rectangles to draw each step of the
            // progress bar.
            progressBarRectangles = gcnew array<Rectangle>(NumberChunks);

            for (int i = 0; i < NumberChunks; i++)
            {
                // Use the thickness defined by the current visual style
                // to calculate the height of each rectangle. The size
                // adjustments ensure that the chunks do not paint over
                // the frame.

                int filledRectangleHeight = 
                    ((i + 1) * (ProgressBarRenderer::ChunkThickness +
                    (2 * ProgressBarRenderer::ChunkSpaceThickness)));

                progressBarRectangles[i] = Rectangle(
                    ClientRectangle.X + 3,
                    ClientRectangle.Y + ClientRectangle.Height - 3
                    - filledRectangleHeight,
                    ClientRectangle.Width - 6,
                    filledRectangleHeight);
            }
        }

        // Handle the timer tick; draw each progressively larger rectangle.
    private:
        void progressTimer_Tick(Object^ myObject, EventArgs^ e)
        {
            if (ticks < NumberChunks)
            {
                Graphics^ g = this->CreateGraphics();
                ProgressBarRenderer::DrawVerticalChunks(g,
                    progressBarRectangles[ticks]);
                ticks++;
            }
            else
            {
                progressTimer->Enabled = false;
            }
        }

        // Start the progress bar.
    public:
        void Start()
        {
            if (ProgressBarRenderer::IsSupported)
            {
                progressTimer->Start();
            }
            else
            {
                MessageBox::Show("VerticalScrollBar requires visual styles");
            }
        }
    };

    public ref class Form1 : public Form
    {
    private:
        VerticalProgressBar^ bar1;
        Button^ button1;

    public:
        Form1() : Form()
        {
            this->Size = System::Drawing::Size(500, 500);
            bar1 = gcnew VerticalProgressBar();
            bar1->NumberChunks = 30;
            button1 = gcnew Button();
            button1->Location = Point(150, 10);
            button1->Size = System::Drawing::Size(150, 30);
            button1->Text = "Start VerticalProgressBar";
            button1->Click += gcnew EventHandler(this, &Form1::button1_Click);
            Controls->AddRange(gcnew array<Control^> { button1, bar1 });
        }

        // Start the VerticalProgressBar.
    private:
        void button1_Click(Object^ sender, EventArgs^ e)
        {
            bar1->Start();
        }
    };
}


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

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

namespace ProgressBarRendererSample
{
    public class Form1 : Form
    {
        private VerticalProgressBar bar1 = new VerticalProgressBar();
        private Button button1 = new Button();

        public Form1()
            : base()
        {
            this.Size = new Size(500, 500);
            bar1.NumberChunks = 30;
            button1.Location = new Point(150, 10);
            button1.Size = new Size(150, 30);
            button1.Text = "Start VerticalProgressBar";
            button1.Click += new EventHandler(button1_Click);
            Controls.AddRange(new Control[] { button1, bar1 });
        }

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

        // Start the VerticalProgressBar.
        private void button1_Click(object sender, EventArgs e)
        {
            bar1.Start();
        }
    }

    public class VerticalProgressBar : Control
    {
        private int numberChunksValue;
        private int ticks;
        private Timer progressTimer = new Timer();
        private Rectangle[] progressBarRectangles;

        public VerticalProgressBar()
            : base()
        {
            this.Location = new Point(10, 10);
            this.Width = 50;

            // The progress bar will update every second.
            progressTimer.Interval = 1000;
            progressTimer.Tick += new EventHandler(progressTimer_Tick);

            // This property also calls SetupProgressBar to initialize 
            // the progress bar rectangles if styles are enabled.
            NumberChunks = 20;

            // Set the default height if visual styles are not enabled.
            if (!ProgressBarRenderer.IsSupported)
            {
                this.Height = 100;
            }
        }

        // Specify the number of progress bar chunks to base the height on.
        public int NumberChunks
        {
            get
            {
                return numberChunksValue;
            }

            set
            {
                if (value <= 50 && value > 0)
                {
                    numberChunksValue = value;
                }
                else
                {
                    MessageBox.Show("Number of chunks must be between " +
                        "0 and 50; defaulting to 10");
                    numberChunksValue = 10;
                }

                // Recalculate the progress bar size, if visual styles 
                // are active.
                if (ProgressBarRenderer.IsSupported)
                {
                    SetupProgressBar();
                }
            }
        }

        // Draw the progress bar in its normal state.
        protected override void OnPaint(PaintEventArgs e)
        {
            base.OnPaint(e);

            if (ProgressBarRenderer.IsSupported)
            {
                ProgressBarRenderer.DrawVerticalBar(e.Graphics,
                    ClientRectangle);
                this.Parent.Text = "VerticalProgressBar Enabled";
            }
            else
            {
                this.Parent.Text = "VerticalProgressBar Disabled";
            }
        }

        // Initialize the rectangles used to paint the states of the 
        // progress bar.
        private void SetupProgressBar()
        {
            if (!ProgressBarRenderer.IsSupported)
            {
                return;
            }

            // Determine the size of the progress bar frame.
            this.Size = new Size(ClientRectangle.Width,
                (NumberChunks) * (ProgressBarRenderer.ChunkThickness +
                (2 * ProgressBarRenderer.ChunkSpaceThickness)) + 6);

            // Initialize the rectangles to draw each step of the 
            // progress bar.
            progressBarRectangles = new Rectangle[NumberChunks];

            for (int i = 0; i < NumberChunks; i++)
            {
                // Use the thickness defined by the current visual style 
                // to calculate the height of each rectangle. The size 
                // adjustments ensure that the chunks do not paint over 
                // the frame.

                int filledRectangleHeight =
                    ((i + 1) * (ProgressBarRenderer.ChunkThickness +
                    (2 * ProgressBarRenderer.ChunkSpaceThickness)));

                progressBarRectangles[i] = new Rectangle(
                    ClientRectangle.X + 3,
                    ClientRectangle.Y + ClientRectangle.Height - 3
                    - filledRectangleHeight,
                    ClientRectangle.Width - 6,
                    filledRectangleHeight);
            }
        }

        // Handle the timer tick; draw each progressively larger rectangle.
        private void progressTimer_Tick(Object myObject, EventArgs e)
        {
            if (ticks < NumberChunks)
            {
                using (Graphics g = this.CreateGraphics())
                {
                    ProgressBarRenderer.DrawVerticalChunks(g,
                        progressBarRectangles[ticks]);
                    ticks++;
                }
            }
            else
            {
                progressTimer.Enabled = false;
            }
        }

        // Start the progress bar.
        public void Start()
        {
            if (ProgressBarRenderer.IsSupported)
            {
                progressTimer.Start();
            }
            else
            {
                MessageBox.Show("VerticalScrollBar requires visual styles");
            }
        }
    }
}

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



Public Class Form1
    Inherits Form
    Private bar1 As New VerticalProgressBar()
    Private button1 As New Button()
    
    
    Public Sub New() 
        Me.Size = New Size(500, 500)
        bar1.NumberChunks = 30
        button1.Location = New Point(150, 10)
        button1.Size = New Size(150, 30)
        button1.Text = "Start VerticalProgressBar"
        AddHandler button1.Click, AddressOf button1_Click
        Controls.AddRange(New Control() {button1, bar1})
    
    End Sub
    
    
    <STAThread()>  _
    Public Shared Sub Main() 
        ' The call to EnableVisualStyles below does not affect
        ' whether ProgressBarRenderer.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
    
    
    ' Start the VerticalProgressBar.
    Private Sub button1_Click(ByVal sender As Object, ByVal e As EventArgs) 
        bar1.Start()
    
    End Sub
End Class


Public Class VerticalProgressBar
    Inherits Control
    Private numberChunksValue As Integer
    Private ticks As Integer
    Private progressTimer As New Timer()
    Private progressBarRectangles() As Rectangle
    
    
    Public Sub New() 
        Me.Location = New Point(10, 10)
        Me.Width = 50
        
        ' The progress bar will update every second.
        progressTimer.Interval = 1000
        AddHandler progressTimer.Tick, AddressOf progressTimer_Tick
        
        ' This property also calls SetupProgressBar to initialize 
        ' the progress bar rectangles if styles are enabled.
        NumberChunks = 20
        
        ' Set the default height if visual styles are not enabled.
        If Not ProgressBarRenderer.IsSupported Then
            Me.Height = 100
        End If
    
    End Sub
    
    ' Specify the number of progress bar chunks to base the height on.
    
    Public Property NumberChunks() As Integer 
        Get
            Return numberChunksValue
        End Get
        
        Set
            If value <= 50 AndAlso value > 0 Then
                numberChunksValue = value
            Else
                MessageBox.Show("Number of chunks must be between " + "0 and 50; defaulting to 10")
                numberChunksValue = 10
            End If
            
            ' Recalculate the progress bar size, if visual styles 
            ' are active.
            If ProgressBarRenderer.IsSupported Then
                SetupProgressBar()
            End If
        End Set
    End Property
    
    
    ' Draw the progress bar in its normal state.
    Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs) 
        MyBase.OnPaint(e)
        
        If ProgressBarRenderer.IsSupported Then
            ProgressBarRenderer.DrawVerticalBar(e.Graphics, ClientRectangle)
            Me.Parent.Text = "VerticalProgressBar Enabled"
        Else
            Me.Parent.Text = "VerticalProgressBar Disabled"
        End If
    
    End Sub
    
    ' Initialize the rectangles used to paint the states of the 
    ' progress bar.
    Private Sub SetupProgressBar() 
        If Not ProgressBarRenderer.IsSupported Then
            Return
        End If
        
        ' Determine the size of the progress bar frame.
        Me.Size = New Size(ClientRectangle.Width, NumberChunks *(ProgressBarRenderer.ChunkThickness + 2 * ProgressBarRenderer.ChunkSpaceThickness) + 6)
        
        ' Initialize the rectangles to draw each step of the 
        ' progress bar.
        progressBarRectangles = New Rectangle(NumberChunks) {}
        
        Dim i As Integer
        For i = 0 To NumberChunks
            ' Use the thickness defined by the current visual style 
            ' to calculate the height of each rectangle. The size 
            ' adjustments ensure that the chunks do not paint over 
            ' the frame.
            Dim filledRectangleHeight As Integer = (i + 1)  _
        *(ProgressBarRenderer.ChunkThickness + 2 * ProgressBarRenderer.ChunkSpaceThickness)
            
            progressBarRectangles(i) = New Rectangle(ClientRectangle.X + 3, _
                ClientRectangle.Y + ClientRectangle.Height - 3 - filledRectangleHeight, _
                ClientRectangle.Width - 6, filledRectangleHeight)
        Next i
    
    End Sub
    
    ' Handle the timer tick; draw each progressively larger rectangle.
    Private Sub progressTimer_Tick(ByVal myObject As [Object], ByVal e As EventArgs) 
        If ticks < NumberChunks Then
            Dim g As Graphics = Me.CreateGraphics()
            Try
                ProgressBarRenderer.DrawVerticalChunks(g, progressBarRectangles(ticks))
                ticks += 1
            Finally
                g.Dispose()
            End Try
        Else
            progressTimer.Enabled = False
        End If
    
    End Sub
    
    ' Start the progress bar.
    Public Sub Start() 
        If ProgressBarRenderer.IsSupported Then
            progressTimer.Start()
        Else
            MessageBox.Show("VerticalScrollBar requires visual styles")
        End If
    
    End Sub
End Class

Remarks

The ProgressBarRenderer class provides a set of static methods that can be used to render a progress bar control with the current visual style of the operating system. Rendering a control refers to drawing the user interface of a control. This is useful if you are drawing a custom control that should have the appearance of the current visual style. To draw a progress bar, use the DrawHorizontalBar or DrawVerticalBar methods to draw the empty bar, and then use the DrawHorizontalChunks or DrawVerticalChunks methods to draw the elements that fill in the bar.

If visual styles are enabled in the operating system and visual styles are applied to the client area of application windows, the methods of this class will draw the progress bar with the current visual style. Otherwise, the methods and properties of this class will throw an InvalidOperationException. To determine whether the members of this class can be used, you can check the value of the IsSupported property.

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.ProgressBar.Bar, System.Windows.Forms.VisualStyles.VisualStyleElement.ProgressBar.BarVertical, System.Windows.Forms.VisualStyles.VisualStyleElement.ProgressBar.Chunk, and System.Windows.Forms.VisualStyles.VisualStyleElement.ProgressBar.ChunkVertical classes. For more information, see Rendering Controls with Visual Styles.

Properties

ChunkSpaceThickness	Gets the width, in pixels, of the space between each inner piece of the progress bar.
ChunkThickness	Gets the width, in pixels, of a single inner piece of the progress bar.
IsSupported	Gets a value indicating whether the ProgressBarRenderer class can be used to draw a progress bar control with visual styles.

Methods

DrawHorizontalBar(Graphics, Rectangle)	Draws an empty progress bar control that fills in horizontally.
DrawHorizontalChunks(Graphics, Rectangle)	Draws a set of progress bar pieces that fill a horizontal progress bar.
DrawVerticalBar(Graphics, Rectangle)	Draws an empty progress bar control that fills in vertically.
DrawVerticalChunks(Graphics, Rectangle)	Draws a set of progress bar pieces that fill a vertical progress bar.

See also

• VisualStyleRenderer
• VisualStyleElement