AutoCAD groups most graphical and nongraphical objects into collections or container objects. Although collections contain different types of data, they can be processed using similar techniques. Each collection has a method for adding an object to or obtaining an item from a collection. Most collections use the Add or SetAt methods to add an object to a collection.
Most collections offer similar methods and properties to make them easy to use and learn. The Count property returns a zero-based count of the objects in a collection, while the Item function returns an object from a collection. Examples of collection members in the AutoCAD .NET API are:
