There are three types of combo boxes: simple, drop down, and drop down list.

All combo boxes show their edit area at all times, but some can show and hide their list box areas. The following table summarizes the properties of each type of combo box.

Style	Can hide list?	Text must match list?
Simple	No	No
Drop down	Yes	No
Drop down list	Yes	Yes

From a user's perspective, these are the distinctions between the different styles of combo boxes:

A simple combo box cannot hide its list box area. Its edit area behaves just like an edit control; the user can enter and edit text, and the text does not need to match one of the items in the list. If the text does match, the corresponding list item is selected.
A drop down combo box behaves like a simple combo box, with one exception. In its initial state, its list area is not displayed. It appears when the user clicks on the icon to the right of the edit area. When drop down combo boxes are not being used, they take up less space than a simple combo box or a list box.
The list area of a drop down list combo box behaves like the list area of a drop down combo box–it appears only when needed. The two combo box types differ in the behavior of their edit areas. Whereas drop down edit areas behave like regular edit controls, drop down list edit areas are limited to displaying only the text from one of their list items. When the edit text matches the item text, no more characters can be entered.

See Also