This macro maps the identifier (ID) of an item to an index. You can use this macro or send the LVM_MAPIDTOINDEX message explicitly.
List-view controls internally track items by index. This can present problems because indexes can change during the control's existence.
You can use this macro to tag an item with an ID when you create the item. You use this ID to guarantee uniqueness during the existence of the list-view control.
If you need to know the index of an item after you create an ID, call LVM_MAPIDTOINDEX with the unique ID and it returns the most current index.
|In a multithreaded environment, you can only be sure the correct index is returned on the thread that hosts the list-view control, not on background threads.|