The list box control window procedure only draws items that are represented by text strings and emphasizes selected items by inverting them.

If an application uses list box controls containing items that are not represented by text strings, or requires that the emphasized state of an item is to be drawn in a special manner, the list box control must specify the style LS_OWNERDRAW and those items must be drawn by the owner.

The list box control window procedure generates this message and sends it to the owner of the list box control, informing the owner that an item is to be drawn, offering the owner the opportunity to draw that item, and indicating that either the item has been drawn, or that the list box control is to draw it.

The item text must not be changed during the processing of this message.