The AutoCompleteBox control does not provide such events. However, you could create your own custom Filtering and HighlightBehaviour and override the FindHighlightedIndex
and the FindMatchingItems
methods. Both of these methods will be called before the completion of the filtering and highlighting of the items and you could use them to achieve what you desired. More detailed information about how to create custom Filtering and HighlightBehaviour you could find on the following links:
Another approach is to use the KeyDown
event that would be fired before the filtering and highlighting of the items.
I hope this will help you.
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