SQL Server 2005 Circular Progress Bar

• Download source files - 11.3 Kb Updated to include double buffering
• Download demo project - 37.9 Kb
• Download C# 1.1 source code - 17 Kb Conversion by Olof Szymczak
• Download C# 2.0 source code - 29.8 Kb Conversion by Olof Szymczak

Introduction

After initially searching for the animation used in SQL Server 2005 as an AVI or GIF, I stumbled across the excellent article by Amr Aly Elsehemy, here at The Code Project. Although good code, and indeed a starting point for what I have created, it didn't actually replicate the look and feel of the Microsoft SQL Server 2005 'busy' animation.

At less than 220 lines, I think that this control is pretty compact, and it seems to perform well, even when other threads in my application are busy.

Code

I store each 'segment' of the progress bar in an array, this makes it easy to iterate through later.

Private segmentPaths(11) As Drawing2D.GraphicsPath

The segments are initialized in the CalculateSegments method, which is called when the control is initialized or resized. This method also generates a region which is used to clip the center circle back out when painting the control.

'Create 12 segment pieces
For intCount As Integer = 0 To 11
    secmentPaths(intCount) = New Drawing2D.GraphicsPath

    'We subtract 90 so that the starting segment is at 12 o'clock
    secmentPaths(intCount).AddPie(rctFull, (intCount * 30) - 90, 25)
Next

The ProgressDisk_Paint method is where all the real work goes on (with the exception of the automatic iteration). I think the code speaks for itself, especially the comments :-)

e.Graphics.SmoothingMode = Drawing2D.SmoothingMode.AntiAlias
e.Graphics.ExcludeClip(innerBackgroundRegion)

For intCount As Integer = 0 To 11
    If Me.Enabled Then
        If intCount = m_TransitionSegment Then
            'If this segment is the transistion segment, colour it differently
            e.Graphics.FillPath(New SolidBrush(m_TransistionColour), _
                                segmentPaths(intCount))
        ElseIf intCount < m_TransitionSegment Then
            'This segment is behind the transistion segment
            If m_BehindIsActive Then
                'If behind the transistion should be active, 
                'colour it with the active colour
                e.Graphics.FillPath(New SolidBrush(m_ActiveColour),_
                                    segmentPaths(intCount))
            Else
                'If behind the transistion should be in-active, 
                'colour it with the in-active colour
                e.Graphics.FillPath(New SolidBrush(m_InactiveColour), _
                                    segmentPaths(intCount))
            End If
        Else
            'This segment is ahead of the transistion segment
            If m_BehindIsActive Then
                'If behind the the transistion should be active, 
                'colour it with the in-active colour
                e.Graphics.FillPath(New SolidBrush(m_InactiveColour),_
                                    segmentPaths(intCount))
            Else
                'If behind the the transistion should be in-active, 
                'colour it with the active colour
                e.Graphics.FillPath(New SolidBrush(m_ActiveColour),_
                                    segmentPaths(intCount))
            End If
        End If
    Else
        'Draw all segments in in-active colour if not enabled
        e.Graphics.FillPath(New SolidBrush(m_InactiveColour), _
                            segmentPaths(intCount))
    End If
Next

The only other real work is done by the timer increment, which is fired by default every 100ms, but this is exposed as a property.

If m_TransitionSegment = 11 Then
    m_TransitionSegment = 0
    m_BehindIsActive = Not m_BehindIsActive
ElseIf m_TransitionSegment = -1 Then
    m_TransitionSegment = 0
Else
    m_TransitionSegment += 1
End If

Invalidate()

The m_BehindIsActive variable decided whether all the segments behind (anti-clockwise) the transision segment (the segment currently changing colour) should be coloured using the active or inactive colour, both of which are user definable.