custom combobox win32

I am trying to implement an auto-suggest feature in an win32 combobox (C++). I want to achieve a behaviour that is similar to the google auto suggest function. When the user types something into the edit-control of the combobox, its listbox opens and shows all possible matches. The Problem is the default behaviour of a win32 combobox is to always select the closest match and put the complete text (selected) into the edit control when the list is opened. I need to avoid this behaviour. The list should just open - dont select something and dont change the text开发者_运维问答 in the edit-control! I have tried to subclass the combobox and catch the CBN_DROPDOWN message, but this changes nothing on the default behavior.

Does anyone have a further idea? I dont want the auto-complete feature that just completes the text in the edit-control without opening the list.

Thx in advance Greets, Michael