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ProgressBarRenderer Class

Note: This class is new in the .NET Framework version 2.0.

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

Namespace: System.Windows.Forms
Assembly: System.Windows.Forms (in system.windows.forms.dll)

public ref class ProgressBarRenderer sealed
public final class ProgressBarRenderer
public final class ProgressBarRenderer

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.

Windows XP Home Edition, Windows XP Professional x64 Edition, Windows Server 2003 Platform Note: Visual styles are supported only on these platforms.

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());
}


System.Object
  System.Windows.Forms.ProgressBarRenderer

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0

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