There is no reason why this property would not be taken into account
unless there is no Weekname column in your db. Have you tried setting
it in NeedDataSource to the chartDef item to see if that would make a
chartDef.PlotArea.XAxis.DataLabelsColumn = "Weekname"
If still having problems, we would appreciate if you send us a runnable project.
However hiding the item labels does not require you to manually create
the series at runtime and your initial problem should be resolved by
setting the ShowLabels property
to false, so if this was the only culprit, you can revert back to the
project you've send me and test it with the above property.
the Telerik team