VisibleRange - shouldn't it change when zooming?

[Alan L]

I'm trying to display a chart's primary axis VisibleRange start and end dates in alternate locations.  The problem is that the properties don't seem to ever fire a change notification and Snoop indicates the values don't change when zooming.

I know the values are read only, but shouldn't they be accessible?
Is there another way to access a chart's VisibleRange start and end?

[Devi Aruna Maharasi Murugan]

Hi Alan, 

  

Thanks for contacting Syncfusion Support. 

You can access the VisibleRange of axis in ActualRangeChanged event, whenever axis range gets changed. 

We have prepared a demo sample based on this to read the VisibleRange of the axes while zooming. 

  

Please refer the code snippet, 

  

XAML 

<chart:SfChart Name="chart" ZoomChanged="chart_ZoomChanged"> 

   

        <chart:SfChart.PrimaryAxis> 

             <chart:CategoryAxis  

                    ActualRangeChanged="CategoryAxis_ActualRangeChanged" /> 

        </chart:SfChart.PrimaryAxis> 

 

        <chart:SfChart.SecondaryAxis> 

                <chart:NumericalAxis                    

                     ActualRangeChanged="NumericalAxis_ActualRangeChanged"/> 

        </chart:SfChart.SecondaryAxis> 

 

    <chart:SfChart.Behaviors> 

        <chart:ChartZoomPanBehavior EnableSelectionZooming="True" 

                                    EnablePanning="True" 

                                    EnableZoomingToolBar="True" 

                                    ToolBarItems="All"/> 

                 

        </chart:SfChart.Behaviors> 

           

 </chart:SfChart> 

 

  

C# 

private void CategoryAxis_ActualRangeChanged(object sender, 

                                     ActualRangeChangedEventArgs e) 

        { 

             

            yStart.Text = chart.SecondaryAxis.VisibleRange.Start.ToString(); 

            yEnd.Text = chart.SecondaryAxis.VisibleRange.End.ToString(); 

        } 

 

        private void NumericalAxis_ActualRangeChanged(object sender,  

                                               ActualRangeChangedEventArgs e) 

        { 

            xStart.Text = chart.PrimaryAxis.VisibleRange.Start.ToString(); 

            xEnd.Text = chart.PrimaryAxis.VisibleRange.End.ToString(); 

        } 

  

  

Please find the output screenshot 

  

1)Before Zooming: 

 

2) After Zooming 

 

 

  

Please find the demo sample from below location 

Sample: VisibleRange129874 

  

Regards, 

Devi 

 

[Alan L]

That gets me something like the behavior I was seeking, but doesn't seem accurate.

As an example, using your example, if I zoom from 19 to 20...

The visual display makes sense...


But the Visible range is given as ~18 to ~19.

[Devi Aruna Maharasi Murugan]

Hi Alan, 

  

Thanks for your update. 

  

Since we have used CategoryAxis as chart primary axis in the demo provided in our last update, the visible range will be corresponding axis label index instead of the actual value. 

  

For example, if you have selected axis between 19 to 20, then the visible range of the CategoryAxis will be 18 to 19(index position of 19^th and 20^th point). 

  

To display the actual value as axis visible range, we can use NumericalAxis instead of CategoryAxis 

  

Please find the code snippet, 

<chart:SfChart Name="chart" > 

 

      <chart:SfChart.PrimaryAxis> 

          <chart:NumericalAxis x:Name="xAxis" 

                               EdgeLabelsVisibilityMode="AlwaysVisible" 

                               Interval="1" 

                                ActualRangeChanged="xAxis_ActualRangeChanged"/> 

     </chart:SfChart.PrimaryAxis> 

 

    <chart:SfChart.SecondaryAxis> 

        <chart:NumericalAxis x:Name="yAxis"   

               ActualRangeChanged="yAxis_ActualRangeChanged"/> 

    </chart:SfChart.SecondaryAxis> 

</chart:SfChart> 

 

  

C# 

 

private void xAxis_ActualRangeChanged(object sender,  

             Syncfusion.UI.Xaml.Charts.ActualRangeChangedEventArgs e) 

   { 

       yStart.Text = chart.SecondaryAxis.VisibleRange.Start.ToString(); 

       yEnd.Text = chart.SecondaryAxis.VisibleRange.End.ToString(); 

   } 

 

private void yAxis_ActualRangeChanged(object sender,  

                 Syncfusion.UI.Xaml.Charts.ActualRangeChangedEventArgs e) 

{ 

      xStart.Text = chart.PrimaryAxis.VisibleRange.Start.ToString(); 

      xEnd.Text = chart.PrimaryAxis.VisibleRange.End.ToString(); 

        

 } 

  

  

Please find the output image, 

  

1)While Zooming 

 

  

2)After Zooming 

 

  

We have prepared a demo sample by using NumericalAxis as chart primary axis for your reference and it can be downloaded from below link, 

  

Sample: VisibleRangeNumericalAxis 

  

Regards, 

Devi