Thank you for the writing.
This scenario is not typical for RadDropDownList since it is a virtualized control. In other words, a few visual items (for example 5 - 8) can hold a number of logical items.
Changing the DataSource
property is a time-consuming operation, because it fully resets all properties
all items (both logical and visual).
You should restore the Text
properties after changing the DataSource
. This is required since RadDropDownList syncs its Text
with the recreated items.
I would like to suggest you to set the Filter
property instead of resetting the DataSource property.
I hope my answer is helpful.
All the best,
the Telerik team