How to create a smooth ProgressBar in Visual Basic .NET or in Visual Basic 2005

This article was previously published under Q323088
For a Microsoft Visual C# .NET version of this article, see 323116.
For a Microsoft Visual Basic 6.0 version of this article, see 190179.

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SUMMARY
This article demonstrates how to create a simple, custom UserControl to create a smooth, scrolling ProgressBar control.

In earlier versions of the ProgressBar control, such as the version that is provided with the Microsoft Windows Common Controls ActiveX control, you can view the progress in two different views. To control these views, you use the Scrolling property, which includes standard and smooth settings. Smooth scrolling produces a solid block of color that represents the progress, and standard scrolling appears segmented and is made up of a series of small blocks or rectangles.

The ProgressBar control that is included with Visual Basic .NET or Visual Basic 2005 supports only the standard setting.

The sample code in this article illustrates how to create a control that supports the following properties:
  • Minimum. This property obtains or sets the lower value for the range of valid values for progress. The default value of this property is zero (0); you cannot set this property to a negative value.
  • Maximum. This property obtains or sets the upper value for the range of valid values for progress. The default value of this property is 100.
  • Value. This property obtains or sets the current level of progress. The value must be in the range that the Minimum and the Maximum properties define.
  • ProgressBarColor. This property obtains or sets the color of the progress bar.
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Create a Custom ProgressBar Control

  1. Follow these steps to create a new Windows Control Library project in Visual Basic .NET or in Visual Basic 2005:
    1. Start Microsoft Visual Studio .NET or Microsoft Visual Studio 2005.
    2. On the File menu, point to New, and then click Project.
    3. In the New Project dialog box, click Visual Basic Projects under Project Types, and then click Windows Control Library under Templates.

      Note In Visual Studio 2005, click Visual Basic under Project Types.
    4. In the Name box, type SmoothProgressBar, and then click OK.
    5. In Project Explorer, rename the default class module from UserControl1.vb to SmoothProgressBar.vb.
    6. In the Properties window for the UserControl object, change the Name property from UserControl1 to SmoothProgressBar.
  2. At this point, you typically inherit from the class of that control and then add the additional functionality to extend an existing control. However, the ProgressBar class is sealed and cannot be inherited. Therefore, you must build the control from the beginning.

    Add the following code to the class module of the UserControl, just after the "Windows Form Designer generated code" section:
    Private min As Integer = 0               ' Minimum value for progress rangePrivate max As Integer = 100             ' Maximum value for progress rangePrivate val As Integer = 0               ' Current progressPrivate barColor As Color = Color.Blue   ' Color of progress meterProtected Overrides Sub OnResize(ByVal e As EventArgs)    ' Invalidate the control to get a repaint.    Me.Invalidate()End SubProtected Overrides Sub OnPaint(ByVal e As PaintEventArgs)    Dim g As Graphics = e.Graphics    Dim brush As SolidBrush = New SolidBrush(barColor)    Dim percent As Decimal = (val - min) / (max - min)    Dim rect As Rectangle = Me.ClientRectangle    ' Calculate area for drawing the progress.    rect.Width = rect.Width * percent    ' Draw the progress meter.    g.FillRectangle(brush, rect)    ' Draw a three-dimensional border around the control.    Draw3DBorder(g)    ' Clean up.    brush.Dispose()    g.Dispose()End SubPublic Property Minimum() As Integer    Get        Return min    End Get    Set(ByVal Value As Integer)        ' Prevent a negative value.        If (Value < 0) Then            min = 0        End If        ' Make sure that the minimum value is never set higher than the maximum value.        If (Value > max) Then            min = Value            min = Value        End If        ' Make sure that the value is still in range.        If (val < min) Then            val = min        End If        ' Invalidate the control to get a repaint.        Me.Invalidate()    End SetEnd PropertyPublic Property Maximum() As Integer    Get        Return max    End Get    Set(ByVal Value As Integer)        ' Make sure that the maximum value is never set lower than the minimum value.        If (Value < min) Then            min = Value        End If        max = Value        ' Make sure that the value is still in range.        If (val > max) Then            val = max        End If        ' Invalidate the control to get a repaint.        Me.Invalidate()    End SetEnd PropertyPublic Property Value() As Integer    Get        Return val    End Get    Set(ByVal Value As Integer)        Dim oldValue As Integer = val        ' Make sure that the value does not stray outside the valid range.        If (Value < min) Then            val = min        ElseIf (Value > max) Then            val = max        Else            val = Value        End If        ' Invalidate only the changed area.        Dim percent As Decimal        Dim newValueRect As Rectangle = Me.ClientRectangle        Dim oldValueRect As Rectangle = Me.ClientRectangle        ' Use a new value to calculate the rectangle for progress.        percent = (val - min) / (max - min)        newValueRect.Width = newValueRect.Width * percent        ' Use an old value to calculate the rectangle for progress.        percent = (oldValue - min) / (max - min)        oldValueRect.Width = oldValueRect.Width * percent        Dim updateRect As Rectangle = New Rectangle()        ' Find only the part of the screen that must be updated.        If (newValueRect.Width > oldValueRect.Width) Then            updateRect.X = oldValueRect.Size.Width            updateRect.Width = newValueRect.Width - oldValueRect.Width        Else            updateRect.X = newValueRect.Size.Width            updateRect.Width = oldValueRect.Width - newValueRect.Width        End If        updateRect.Height = Me.Height        ' Invalidate only the intersection region.        Me.Invalidate(updateRect)    End SetEnd PropertyPublic Property ProgressBarColor() As Color    Get        Return barColor    End Get    Set(ByVal Value As Color)        barColor = Value        ' Invalidate the control to get a repaint.        Me.Invalidate()    End SetEnd PropertyPrivate Sub Draw3DBorder(ByVal g As Graphics)    Dim PenWidth As Integer = Pens.White.Width    g.DrawLine(Pens.DarkGray, _        New Point(Me.ClientRectangle.Left, Me.ClientRectangle.Top), _        New Point(Me.ClientRectangle.Width - PenWidth, Me.ClientRectangle.Top))    g.DrawLine(Pens.DarkGray, _        New Point(Me.ClientRectangle.Left, Me.ClientRectangle.Top), _        New Point(Me.ClientRectangle.Left, Me.ClientRectangle.Height - PenWidth))    g.DrawLine(Pens.White, _        New Point(Me.ClientRectangle.Left, Me.ClientRectangle.Height - PenWidth), _        New Point(Me.ClientRectangle.Width - PenWidth, Me.ClientRectangle.Height - PenWidth))    g.DrawLine(Pens.White, _        New Point(Me.ClientRectangle.Width - PenWidth, Me.ClientRectangle.Top), _        New Point(Me.ClientRectangle.Width - PenWidth, Me.ClientRectangle.Height - PenWidth))End Sub					
  3. On the Build menu, click Build Solution to compile the project.
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Create a Sample Client Application

  1. On the File menu, point to New, and then click Project.
  2. In the Add New Project dialog box, click Visual Basic Projects under Project Types, click Windows Application under Templates, and then click OK.
  3. Follow these steps to add two instances of the SmoothProgressBar control to the form:
    1. On the Tools menu, click Customize Toolbox.
    2. Click the .NET Framework Components tab.
    3. Click Browse, and then locate the SmoothProgressBar.dll file, which you created in the "Create a Custom ProgressBar Control" section.
    4. Click OK. Notice that the SmoothProgressBar control is added to the toolbox.
    5. Drag two instances of the SmoothProgressBar control from the toolbox to the default form of the Windows Application project.
  4. Drag a Timer control from the toolbox to the form.
  5. Add the following code to the Tick event of the Timer control:
    If (Me.SmoothProgressBar1.Value > 0) Then    Me.SmoothProgressBar1.Value -= 1    Me.SmoothProgressBar2.Value += 1Else    Me.Timer1.Enabled = FalseEnd If					
  6. Drag a Button control from the toolbox to the form.
  7. Add the following code to the Click event of the Button control:
    Me.SmoothProgressBar1.Value = 100Me.SmoothProgressBar2.Value = 0Me.Timer1.Interval = 1Me.Timer1.Enabled = True					
  8. On the Debug menu, click Start to run the sample project.
  9. Click the button. Notice that the two progress indicators display the text "progress". One progress indicator displays the progress in an increasing manner, and the other progress indicator displays the progress in a decreasing or a countdown manner.
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progress bar
Properties

Article ID: 323088 - Last Review: 12/06/2006 22:47:55 - Revision: 3.3

Microsoft Visual Basic .NET 2002 Standard Edition, Microsoft Visual Basic .NET 2003 Standard Edition, Microsoft Visual Basic 2005

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