The PAPI object model illustrated in this chapter primarily focuses on the objects that are most commonly used. Objects in the model that correspond to the following entities in CMS are referred to as principal objects: Context, Channel, Posting, Template, TemplateGallery, Resource, ResourceGallery, Placeholder, and PlaceholderDefinition. These are all discussed in detail from an API perspective in the chapters that follow. Principal objects are the tangible objects that are frequently accessed in an ASPX code-behind in template files. For instance, dynamic navigation and breadcrumbs are typically generated using the channel hierarchy and Posting collections on nearly every page of most sites.
We have also included in the object model the following support objects in CMS, referred to as auxiliary objects: CustomProperty, CustomPropertyDefinition, Searches, SessionSettings, User, and various collections (most of which are covered in the illustrated model).
Some objects are not depicted in our PAPI object model. These objects implement a wide range of concepts in the current release of CMS but don't fit easily into a graphical representation. These include publishing events (which enable code-based customization of workflow), the Web Author, caching of whole and partial Web pages, limited security, and processing exceptions.