Dynamic adding of data not working

[Florian Reitz]

Hello,

previously I was using SfChart on Xamarin.Android with the DataSource property of the LineSeries with an ObservableArrayList. I was adding ChartDataPoints to this list on runtime and the chart refreshed itself properly.

However this did only work on Android devices with API <= 25. On API 26+ (Oreo) the chart always stayed empty.

Beacuse of this and th fact that the DataSource property is marked as deprecated, I tried to use the ItemsSource property of LineSeries with an ObservableCollection, but I can't get it to work on all APIs. 

Please find the following example and note that it does not work with ChartDataPoint, either.

public class ChartFragment : Fragment

{

    private SfChart _chart;

    private ObservableCollection _chartData;

    public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)

    {

        View view = inflater.Inflate(Resource.Layout.Chart, container, false);

        _chartData = new ObservableCollection();

        LineSeries dataSeries = new LineSeries();

        dataSeries.XBindingPath = nameof(MeasurementPoint.Timestamp);

        dataSeries.YBindingPath = nameof(MeasurementPoint.Value);

        dataSeries.DataSource.ItemsSource = _chartData;

        _chart = new SfChart(Activity);

        _chart.Series.Add(dataSeries);

        DateTimeAxis primaryAxis = new DateTimeAxis();

        primaryAxis.Title.Text = "Time";

        primaryAxis.LabelRotationAngle = -45;

        primaryAxis.LabelStyle.LabelFormat = "HH:mm:ss";

        _chart.PrimaryAxis = primaryAxis;

        NumericalAxis secondaryAxis = new NumericalAxis();

        secondaryAxis.Title.Text = "Value";

        _chart.SecondaryAxis = secondaryAxis;

        LinearLayout layout = view.FindViewById(Resource.Id.chartLinearLayout2);

        layout.AddView(_chart);

        return view;

    }

    public void AddValues(DateTime dateTime, double value)

    {

         _chartData.Add(new MeasurementPoint(dateTime, value));

    }

    private class MeasurementPoint

    {

        public DateTime Timestamp { get; set; }

        public double Value { get; set; }

        public MeasurementPoint(DateTime timestamp, double value)

        {

            Timestamp = timestamp;

            Value = value;

        }

    }

}

Thanks, Florian

[Divya Venkatesan]

Hi Florian, 

 

Thanks for using Syncfusion products. 

 

We have prepared a sample based on your provided details. The sample works fine and we have attached the sample for your reference. Could you please check with the sample in below location? 

 

Sample: http://www.syncfusion.com/downloads/support/forum/137118/ze/ChartSample-211683812  

 

If still you face the problem, please revert us by modifying the sample based on your application along with replication procedure. This would be helpful for us to serve you. 

 

Regards, 

Divya Venkatesan