UpdateGridLines NullReferenceException
Hi
I have recently upgraded my WPF project from .Net Framework 4.8 to .Net 6 and now I get an exception that previously worked.
Basically I have a SfChart with two different PrimaryAxis (one a DateTime axis, one a TimeSpan axis) that can be switched with a Toggle button.
The switch from one to the other works, but switching back to the original one always fails because of a NullReferenceExcepion.
Anyone experienced something similar and solved it?
Chart snippet:
<xamlExtensions:SfChartExtension x:Name="LiveDataChart" Grid.Row="0" Grid.Column="0"
Margin="0,0,3,0"
Source="{Binding DataSeries, UpdateSourceTrigger=PropertyChanged}">
<xamlExtensions:SfChartExtension.PrimaryAxis>
<MultiBinding>
<MultiBinding.Converter>
<converters:PrimaryAxisMultiConverter />
</MultiBinding.Converter>
<Binding Path="ChartSettings.TimeAxis.DisplayAsTimeSpan" />
<Binding Source="{StaticResource LiveDataPrimaryTimeSpanAxis}"/>
<Binding Source="{StaticResource LiveDataPrimaryDateTimeAxis}"/>
</MultiBinding>
</xamlExtensions:SfChartExtension.PrimaryAxis>
<xamlExtensions:SfChartExtension.SeriesTemplateSelector>
<templateSelector:SeriesDataTemplateSelector LineSeriesTemplate="{StaticResource LiveDataLineSeriesTemplate}" />
</xamlExtensions:SfChartExtension.SeriesTemplateSelector>
<xamlExtensions:SfChartExtension.Behaviors>
<syncfusion:ChartZoomPanBehavior EnableMouseWheelZooming="True" EnablePinchZooming="True" EnableSelectionZooming="True"
EnableZoomingToolBar="{Binding Path=IsChecked, Mode=TwoWay, Source={x:Reference ZoomingToolbarToggleButton}}"
ToolBarItemHeight="20" ToolBarItemMargin="5" ToolBarItemWidth="20"
ZoomMode="XY"/>
<syncfusion:ChartTrackBallBehavior x:Name="ChartTrackball" UseSeriesPalette="True" />
</xamlExtensions:SfChartExtension.Behaviors>
</xamlExtensions:SfChartExtension>
Axis snippets:
<chart:DateTimeAxis x:Key="LiveDataPrimaryDateTimeAxis" ShowGridLines="True" PlotOffset="10"
MajorGridLineStyle="{StaticResource GridLineStyle}" MinorGridLineStyle="{StaticResource GridLineStyle}">
<chart:DateTimeAxis.LabelTemplate>
<DataTemplate DataType="chart:ChartAxisLabel">
<Grid Width="70" Height="60">
<TextBlock FontSize="12"
Text="{Binding LabelContent}"
TextWrapping="Wrap" />
</Grid>
</DataTemplate>
</chart:DateTimeAxis.LabelTemplate>
</chart:DateTimeAxis>
<chart:TimeSpanAxis x:Key="LiveDataPrimaryTimeSpanAxis"
EnableScrollBar="{Binding ChartSettings.TimeAxis.ScrollbarVisible}"
LabelsPosition="Outside"
ShowGridLines="True"
PlotOffset="10"
LabelFormat="mm\:ss\:fff"
MinorGridLineStyle="{StaticResource GridLineStyle}"
MajorGridLineStyle="{StaticResource GridLineStyle}"
ShowTrackBallInfo="{Binding ChartSettings.TrackballTooltipDateTimeAxis}">
<chart:TimeSpanAxis.LabelTemplate>
<DataTemplate DataType="chart:ChartAxisLabel">
<Grid Width="70" Height="60">
<TextBlock FontSize="12"
Text="{Binding LabelContent}"
TextWrapping="Wrap" />
</Grid>
</DataTemplate>
</chart:TimeSpanAxis.LabelTemplate>
</chart:TimeSpanAxis>
Converter Snippet:
public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
{
if (values.Length < 3 || values[0] is not bool || values[1] is not ChartAxisBase2D || values[2] is not ChartAxisBase2D)
{
return DependencyProperty.UnsetValue;
}
var dateTimeAxis = (bool) values[0];
return dateTimeAxis ? values[1] : values[2];
}
Thanks for the reply!
I checked your sample and it works indeed. But I could replicate the error with a small change. If the axis are the same instance as before the change I get the exact same issue as in my original question:
public partial class MainWindow : Window
{
public List<DateTime> TimeData { get; set; }
public TimeSpanAxis TimeSpanAxis { get; set; }
public DateTimeAxis DateTimeAxis { get; set; }
public MainWindow()
{
InitializeComponent();
TimeSpanAxis = new TimeSpanAxis();
DateTimeAxis = new DateTimeAxis();
}
private void Button_Click1(object sender, RoutedEventArgs e)
{
sfChartExt.PrimaryAxis = TimeSpanAxis;
}
private void Button_Click2(object sender, RoutedEventArgs e)
{
sfChartExt.PrimaryAxis = DateTimeAxis;
}
}
Process:
- Select DateTimeAxis -> works
- Select TimeSpanAxis -> works
- Select DateTimeAxis again -> crash
Hello Lukas,
We have discussed the reported issue with our development team. The exception is occurring due to the disposal of axis items, which is done to prevent memory leaks and improve performance.
However, we can resolve this issue by using the Clone method in the axis. This method is used to carry forward the axis settings from the initialized property. For your reference, we have provided a code snippet, a demo, and a runnable sample below.
|
public partial class MainWindow : Window { public TimeSpanAxis TimeSpanAxis { get; set; } public DateTimeAxis DateTimeAxis { get; set; }
public MainWindow() { InitializeComponent(); TimeSpanAxis = new TimeSpanAxis() { Background = new SolidColorBrush(Colors.Aqua), PlotOffset=20, EdgeLabelsDrawingMode=EdgeLabelsDrawingMode.Shift }; DateTimeAxis = new DateTimeAxis() { Background = new SolidColorBrush(Colors.LimeGreen), PlotOffset = 20, EdgeLabelsDrawingMode = EdgeLabelsDrawingMode.Shift }; }
private void Button_Click1(object sender, RoutedEventArgs e) { sfChartExt.PrimaryAxis = (ChartAxisBase2D)TimeSpanAxis.Clone(); }
private void Button_Click2(object sender, RoutedEventArgs e) { sfChartExt.PrimaryAxis = (ChartAxisBase2D)DateTimeAxis.Clone(); } } |
Please don't hesitate to reach out if you require any further assistance.
Best regards,
Saiyath Ali Fathima M
Attachment: Chart_6d2ae4.zip
