Hi Fergus Bown,
Unfortunately RadChart does not provide support for reversing the XAxis item order and it would not be possible to achieve the desired functionality.
You can handle the BeforeLayout server side event and customize the axis item labels like this:
|foreach (ChartAxisItem axisItem in RadChart1.PlotArea.XAxis.Items)
| axisItem.TextBlock.Text = "Custom";
but this will not change the underlying axis item values i.e. they will still be ordered from low to high and this only changes the visual appearance of the items.
the Telerik team
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