A class is a list of related methods and properties that are used together to work with a specific item or task. For example, a class may contain methods and properties used to work with a word processing document. An object is an instance of a class. It is a combination of data for an item, such as a word processing document, and the properties and methods used to work with the item.
Applications that implement COM typically have classes for each of the items you can work with in the application. You will use the appropriate class to create an object for each item you want to work with. Once the object is created, you will use the object’s methods and properties to interact with the object. For example, Microsoft Excel has classes for each of the items you typically work with, such as worksheets and charts.
In your Dexterity-based application, you will use the Class Browser window to examine the classes an application makes available through COM. The Class Browser lists the properties and methods available for each class.