I am adding my reply to your ticket in this forum thread as well.
Indeed, deleting 1 000 000 records from the RadGridView takes a large amount of time to complete. As you are using RadObservableCollection as ItemsSource, you can get the benefits of its AddRange
method as when it is applied all notifications to the RadGridView are suspended and thus the performance is boosted:
sender, RoutedEventArgs e)
var items =
var itemsToRemove =
The aforementioned approach decreases the time for the items deletion. Still, as 1 000 000 items is a pretty huge number, there is some significant period of waiting. If you need to clear all the items from the collection, I suggest you use its Clear method directly:
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