Why my tooltip is not showing?

[ardmore]

I used MVVM to create a data source(property), then I use RadCartesianChart to plot it. It works but I can not see the tooltip when hover mouse to the bars.

<telerik:ChartDataSource x:Name="ChartDataSource1" Items="{Binding Sales}" />

<telerik:RadCartesianChart x:Name="barSeries">
   <telerik:RadCartesianChart.Behaviors>
      <telerik:ChartTooltipBehavior="Top" VerticalOffset="20" />
   </telerik:RadCartesianChart.Behaviors>
   <telerik:RadCartesianChart.TooltipTemplate>
        <DataTemplate>
           <Grid>
            <Path Data="M-1236,-441 L-1180,-441 -1180,-424 -1228,-424 -1230.5,-420 -1233,-424 -1236,-424 z"
                      Stretch="Fill" Fill="Beige" Stroke="Gray" StrokeThickness="2"/>
                <StackPanel Margin="5,5,5,18">
                    <StackPanel Orientation="Horizontal">

                        <TextBlock Text="{Binding Path=DataItem.Quarter}" FontWeight="Bold" FontSize="11"/>
                       </StackPanel>
           </Grid>
        </DataTemplate>
        <telerik:RadCartesianChart.Grid>
             <telerik:CartesianChartGrid MajorLinesVisibility="XY"
                                         MajorYLineDashArray="10,5"
                                         MajorXLinesRenderMode="All"
            </telerik:CartesianChartGrid>
        </telerik:RadCartesianChart.Grid>
    <telerik:RadCartesianChart.HorizontalAxis>
        <telerik:CategoricalAxis/>
    </telerik:RadCartesianChart.HorizontalAxis>
    <telerik:RadCartesianChart.VerticalAxis>
        <telerik:LinearAxis/>
    </telerik:RadCartesianChart.VerticalAxis>
    <telerik:BarSeries CategoryBinding="Quarter" ValueBinding="Profit" Items="{Binding Element=ChartDataSource1}"/>
</telerik:RadCartesianChart>

Thanks

 

[Dinko | Tech Support Engineer]

Hi Hui Zhao,

Thank you for your interest in RadChartView control.

This behavior is expected when you have used ChartDataSource. Basically, the DataItem property no longer points to a view model from your collection. The sampling combines several data items into a single data point. In this case, the DataItem property of the DataPoint holds a reference to an object of type DataPointSamplingInfo which holds information about the sampled data and the aggregate used to sample it. You can read more about this behavior in the DataPointSamplingInfo section in our documentation. 

In your case, you can remove the DataItem from the binding. Attached to this reply you can find sample project based on the provided code snippet which demonstrates this approach. Hope this information is helpful.

Regards,
Dinko
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