IDataRenderer | --IItemDataRenderer
IItemDataRenderer interface.
IItemDataRenderer defines the interface that an item renderer needs to implement. Besides the Data property, a list item renderer also needs to provide ItemIndex and ItemType property.
Returns a value indicating the zero-based index of the item in the corresponding data control's item collection.
If the item is not in the collection (e.g. it is a header item), it returns -1.
Sets the zero-based index for the item.
If the item is not in the item collection (e.g. it is a header item), -1 should be used.