Performance problems

[Andy]

Hi

I think I'm seeing a regression in the current build with regards to the charts rendering performance. My example is mapping 24 data points on a line series. In the previous build I saw a slight freezing of the UI when initial rendering takes place (milliseconds although I never did any significant testing), now however I'm seeing a much longer freezing of the UI (nearly a second) while the chart is rendering which is causing a problem with my application as the users are constantly changing data and we wish for that to be immediately re-rendered on the chart but the UI freeze on the render makes it a difficult. I've got some test code below, if you press the refresh button you will see a noticiable freeze of the UI. 

Any ideas, thoughts would be appreciated.

Thanks

Andy

public partial class Page : UserControl
    {
        ObservableCollection<TestObject> testCollection;

        public Page()
        {
            InitializeComponent();
            testCollection = new ObservableCollection<TestObject>();

            SeriesMapping SeriesMapping1 = new SeriesMapping();
            SeriesMapping1.ItemMappings.Add(new ItemMapping("Value", DataPointMember.YValue));
            SeriesMapping1.SeriesDefinition = new LineSeriesDefinition();
            testChart.SeriesMappings.Add(SeriesMapping1);
            testChart.ItemsSource = testCollection;

            DefineData();

        }

        private void DefineData()
        {
            testCollection.Clear();
            for (int i = 0; i < 23; i++)
            {
                Random r = new Random();
                testCollection.Add(new TestObject() { Value = r.Next(0, 20000) });
            }
        }

        public class TestObject
        {
            public double Value { get; set; }
        }

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            DefineData();
        }
    }

//xaml

<UserControl x:Class="TelerikChartPerf.Page"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:telerikChart="clr-namespace:Telerik.Windows.Controls.Charting;assembly=Telerik.Windows.Controls.Charting"
    xmlns:telerikControls="clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Controls.Charting">
    <Grid x:Name="LayoutRoot" Background="White">
        <Grid.RowDefinitions>
            <RowDefinition Height="300" />
            <RowDefinition Height="25" />
        </Grid.RowDefinitions>
        <telerikControls:RadChart Grid.Row="0" Width="500" Height="300" x:Name="testChart" />
        <Button Content="refresh" Grid.Row="1" Click="Button_Click" />
    </Grid>
</UserControl>

[Dwight]

Hello Andy,

The issue comes from the fact, that on each update of the series, an invalidation of the chart is triggered. That includes invalidation of the X and Y ranges and the whole UI.

To speed-up the update, please, try the following:

private void DefineData()
{
  testCollection.Clear();
  // Suspend notifications to stop unnecessary updates.
  testCollection.SuspendNotifications();

  for (int i = 0; i < 23; i++)
  {
     Random r = new Random();
     testCollection.Add(new TestObject() { Value = r.Next(0, 20000) });
  }
  // Resume notifications (that will trigger updates if changes in the collection occured during the suspended notifications)
  testCollection.ResumeNotifications();
}

Best,
Evtim
the Telerik team

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