Speedup MSChart Clear Data Points

Problem Statement

Clearing data points in MSChart is known to be very slow.

• http://connect.microsoft.com/VisualStudio/feedback/details/596212/performance-problem-in-mschart-datapointcollection-clear

Solution

However, there is a workaround for this problem. The suggested workaround from link stated above is as below:

public void ClearPointsQuick()
{
    Points.SuspendUpdates();
    while (Points.Count > 0)
        Points.RemoveAt(Points.Count - 1);
    Points.ResumeUpdates();
    Points.Clear(); //NOTE 1
}

Extension method implementation is as below:

internal static class MSChartExtension
{
    public static void ClearPoints(this Series sender)
    {
        sender.Points.SuspendUpdates();
        while (sender.Points.Count > 0)
            sender.Points.RemoveAt(sender.Points.Count - 1);
        sender.Points.ResumeUpdates();
        sender.Points.Clear(); //NOTE 1
    }
}

(NOTE 1): I added one additional line Points.Clear() at the end of the function to ensure the chart axis updated correctly on next plot. Without adding this line, I observed that previous axis settings will be used when plotting new data points right after calling ClearPoints().

See Also

MSChart Extension: An extension package for MSChart component which contains these fixes and other features.

Revision History

• 31/03/2012: Added additional line to force axis update on next plot (NOTE 1)
• 12/03/2012: Initial release