ProgressBarRenderer Class

 

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)

System.Object
  System.Windows.Forms.ProgressBarRenderer

Public NotInheritable Class ProgressBarRenderer

NameDescription
System_CAPS_pubpropertySystem_CAPS_staticChunkSpaceThickness

Gets the width, in pixels, of the space between each inner piece of the progress bar.

System_CAPS_pubpropertySystem_CAPS_staticChunkThickness

Gets the width, in pixels, of a single inner piece of the progress bar.

System_CAPS_pubpropertySystem_CAPS_staticIsSupported

Gets a value indicating whether the ProgressBarRenderer class can be used to draw a progress bar control with visual styles.

NameDescription
System_CAPS_pubmethodSystem_CAPS_staticDrawHorizontalBar(Graphics, Rectangle)

Draws an empty progress bar control that fills in horizontally.

System_CAPS_pubmethodSystem_CAPS_staticDrawHorizontalChunks(Graphics, Rectangle)

Draws a set of progress bar pieces that fill a horizontal progress bar.

System_CAPS_pubmethodSystem_CAPS_staticDrawVerticalBar(Graphics, Rectangle)

Draws an empty progress bar control that fills in vertically.

System_CAPS_pubmethodSystem_CAPS_staticDrawVerticalChunks(Graphics, Rectangle)

Draws a set of progress bar pieces that fill a vertical progress bar.

System_CAPS_pubmethodEquals(Object)

Determines whether the specified object is equal to the current object.(Inherited from Object.)

System_CAPS_pubmethodGetHashCode()

Serves as the default hash function. (Inherited from Object.)

System_CAPS_pubmethodGetType()

Gets the Type of the current instance.(Inherited from Object.)

System_CAPS_pubmethodToString()

Returns a string that represents the current object.(Inherited from Object.)

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.

WinXpFamily

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.

Imports System
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 'NewNew


    <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 'Main


    ' Start the VerticalProgressBar.
    Private Sub button1_Click(ByVal sender As Object, ByVal e As EventArgs) 
        bar1.Start()

    End Sub 'button1_Click
End Class 'Form1


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 'NewNew

    ' 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 'OnPaint

    ' 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 'SetupProgressBar

    ' 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 'progressTimer_Tick

    ' Start the progress bar.
    Public Sub Start() 
        If ProgressBarRenderer.IsSupported Then
            progressTimer.Start()
        Else
            MessageBox.Show("VerticalScrollBar requires visual styles")
        End If

    End Sub 'Start
End Class 'VerticalProgressBar

.NET Framework
Available since 2.0

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

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