How do I get access to which .net forms combobox autocomplete suggestions are currently suggested in the drop down suggestion box

I've got some comboboxes which are populated with large collections of items. The user is only allowed to select an existing item, not add one. Currently I just disabled whatever weird property it was (I forgot already!) that allows editing of the combobox. However I figure it would be better if I allowed them to start typing, and let autocomplete search for a list of allowed values.

This is all fine and dandy so far, but I want to maintain some kind of list of last seen autocomplete suggestions so that if they press one key too many and attempt to leave then the combobox text value will revert to the last known good suggestion instead of just clearing what they entered.

To this end, I need to know.开发者_如何学运维. how do I find out at run time which autocomplete suggestions are currently suggested? I figure I'll keep updating the last known good suggestion every keypress...

Thanks in advance for your help guys & gals.