Arc engine-ilayer.

Ilayer
The ilayer interface is implemented by layer objects, which are used to display space information in the map.
Note: LayersExcluding Spatial DataIt is just a reference layer for getting data. A layer object is an abstract object that defines the common methods and attributes of all layers. It has many subclasses, such as ifeaturelayer, igeofeaturelayer, icadfeaturelayer, and irasterlayer.
A layer is equivalent to a vector of elements. When an ArcMap is used to open a element class, it becomes a layer.

For example, the ifeaturelayer interface is used to manage the information of the featureclass layer.

Arc engine-ilayer.