SciChart: ColumnChart - DataSeries.Append

Question

A potential problem I noticed in SciChart for WPF

take the standard example for ColumnChart from SDK (2D Charts - Column Chart)
build and run; the result is as below:

make the following code changes (see (1) and (2))

private void ColumnChartExampleViewOnLoaded(object sender, RoutedEventArgs e)
{

    var dataSeries = new XyDataSeries<double, double> {SeriesName = "Histogram"};

    var yValues = new double[] { 0.1, 0.2, 0.4, 0.8, 1.1, 1.5, 2.4, 4.6, 8.1, 11.7, 14.4, 16.0, 13.7, 10.1, 6.4, 3.5, 2.5, 1.4, 0.4, 0.1};

    using (this.sciChart.SuspendUpdates())
    {
        for (int i = 0; i < yValues.Length; i++)
        {
            // DataSeries for appending data
            dataSeries.Append(i, yValues[i]);
        }

        this.columnSeries.DataSeries = dataSeries;
        this.columnSeries.DataSeries.AcceptsUnsortedData = true; //(1)
    }

    dataSeries.Append(0, 1); //(2)
    this.sciChart.ZoomExtents();
}

and here is the result:

I.e. if I use Append method for the X val which already exists - the UI bars are changing to the lines. I do not know if it is expected behavior or not but for my case I'm updating the Histogram on fly and quite often same X value is having new Y value(s). As a result - the UI behavior confuses... I found workaround for my case (I'm using the Update method since X and index is the same for my case) so this is just a notice.

I'm not sure will you change the behavior or not - just sharing my experience for now...

score 1 · Accepted Answer · answered May 28 '18 at 11:20

SciChart's column series automatically calculates the width of the data-points based on the columns you have available.

If you have columns 0,1,2,3,4,5,6,7,8,9 ...then add a new column at position 0, this calculation goes haywire.

Ways of avoiding this side-effect are:

Update items rather than append new columns with overlapping values
Override column width calculation using the properties FastColumnRenderableSeries.UseUniformWidth and FastColumnRenderableSeries.DataPointWidth
(Advanced) Override column width calculation by overriding GetDataPointWidth() method.

Find out more how the Column series works at the SciChart WPF Documentation page.

SciChart: ColumnChart - DataSeries.Append

1 Answers1