Thank you for writing.
Currently, the only possible way to achieve what you want is to iterate the items and make the comparison yourself. Alternatively, if you are using .NET3.5 or above, you can use LINQ:
List<ListViewDataItem> contains = radListView1.Items.Where(x =>
(contains.Count > 0)
//the item exists in the collection
I hope this helps.
the Telerik team