Sampling with string values

[Courouble Damien]

Hi guys,

I'm trying to enable sampling on a collection of 60 items.
I wanna sample of 20 so i've put 

<telerik:RadChart.SamplingSettings>
              <telerik:SamplingSettings SamplingThreshold="30" SamplingFunction="Average"  />
          </telerik:RadChart.SamplingSettings>

On the xaml part and this code on the vb part

Dim seriesMapping As New SeriesMapping()
        seriesMapping.CollectionIndex = tI
        seriesMapping.LegendLabel = tChartData.SeriesName(tI).ToString
        seriesMapping.ItemMappings.Add(New ItemMapping("X", DataPointMember.XValue) With {.FieldType = GetType(String)})
        seriesMapping.ItemMappings.Add(New ItemMapping("Y", DataPointMember.YValue))

        Dim t As New LineSeriesDefinition()
        t.ShowItemLabels = False
        t.ShowPointMarks = False
        t.ShowItemToolTips = False
        seriesMapping.SeriesDefinition = t

        RadChart1.SeriesMappings.Add(seriesMapping)

This code is working very nice when i have some DateTime to Bind on the XAxis ( Even when i have more than 20000 records) 

But Having some name ( strings) on the Axis X render items numbers instead of items name ( 1 instead of "mystring", 2 instead of "mysecondstring" )

Any chance to display the correct label ?

Thanks,

Damien

[Giuseppe]

Hi Courouble Damien,

Unfortunately this is not possible -- when sampling is enforced, certain information is lost (individual values of YValue, XCategory, etc) as several datapoints are aggregated into one. And while RadChart allows you to choose how the YValue of the resulting datapoint is calculated, it is not possible to provide the same functionality for XCategory as each category is individual and meaningful (the control cannot guess what is the average between let's say "Apples" and "Bananas").

If you would like to display string categories along the XAxis, you will need to disable the sampling mechanism by setting SamplingThreshold to 0.


Regards,
Giuseppe
the Telerik team