It's not exactly what you're asking for, but may be usefull. You can implement autocompletion mechanism. It will check names while user types names in. To use it, you have to use ComboBox control, and fill properties:
Items - with contact collection.
AutoCompleteMode - to Apped.
AutoCompleteSource - to ListItems.
To get contacts from your Outlook, use Office Interop Assemblies.
http://msdn.microsoft.com/en-us/library/15s06t57%28v=vs.80%29.aspx[
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