Question: In which event for a ComboBox that has a DrawMode of OwnerDrawVariable is it most appropriate to set the ComboBox's DropDownHeight?

I am currently setting the DropDownHeight value within the DrawItem event but this seems inefficient.

Edit:

The reason I ask is that I can not get the DropDown window height to be "just right". It is always a little bit too tall or too short.

Answer: 
Incorrect DropDownHeight for ComboBoxes that have DrawMode of OwnerDrawVariable is known issue that has be answered at [Unable to set the DropDownHeight of ComboBox](https://stackoverflow.com/questions/1245530), and I have added the c# code that I use to solve my problem as part of the answer.
Put it in the event DropDown - or override for ComboBox.OnDropDown