In general, clicking Enter key while typing in the input field of the AutoCompleteBox selects the first filtered item. You could simulate this behavior on button click by getting the FilteredItems
of the AutoCompleteBox and add the first item from the collection to the SelectedItems
of the control.
If this is not the case, I'd ask you to explain in more details the scenario and the required result.
I am looking forward to your reply.
Check out Telerik Analytics, the service which allows developers to discover app usage patterns, analyze user data, log exceptions, solve problems and profile application performance at run time. Watch the videos
and start improving your app based on facts, not hunches.