ProgressBarRenderer Class
Provides methods used to render a progress bar control with visual styles. This class cannot be inherited.
Assembly: System.Windows.Forms (in System.Windows.Forms.dll)
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.
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 'New <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 'New ' 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
Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.