| BaseCollection | Collection of BaseItem Items. |
| BaseItem | Base information found in every ProjectTask object. |
| ChangeObjectCollectionT | Collection of ChangeObjectItem Items, which itself raises events when the contents of this collection or when the property of one of its items have changed. |
| ChangeObjectItem | The object whose changes will raise an event. |
| CollectionChangeEventArgs | General collection change event arguments. |
| CommentCollection | Collection of CommentItem Items. |
| CommentItem | Information about a single comment post. |
| ContactAllocationCollection | Collection of ContactAllocationItem Items. |
| ContactAllocationItem | Information about time allocations made to a contact. |
| ContactCollection | Collection of ContactItem Items. |
| ContactItem | Information about an individual contact. |
| DateRangeCollection | Collection of DateRangeItem Items. |
| DateRangeItem | Definition of the Time between two Dates. |
| DependencyCollection | Collection of DependencyItem Items. |
| DependencyItem | Information relating a single dependency to the project or task dependent upon it. |
| FreeBusyCollection | Collection of FreeBusyItem Items. |
| FreeBusyItem | Information about a resource's availability, associated with a task. |
| ItemEventArgsT | Specialized item event args in the data type of the item. |
| MultilineString | A list of single-line strings that can support a multi-line document. |
| OrganizationCollection | Collection of OrganizationItem Items. |
| OrganizationItem | Information about a single organization. |
| ProjectContext | Complete application context information about an entire set of projects, tasks, resources, and schedules. |
| ProjectTaskUtil | Utilities and functionality for the ProjectTask library. |
| PropertyChangeEventArgs | General panel property change event arguments. |
| PropertyCollection | Collection of PropertyItem Items. |
| PropertyItem | Individual property definition. |
| ScheduleEngine | Automated scheduling engine. |
| TaskCollection | Collection of TaskItem Items. |
| TaskItem | Information about an individual project or task. |
| TaskStatusCollection | Collection of TaskStatusItem Items. |
| TaskStatusItem | Information about a status state that can be assigned to a project or task. |
| TaskTypeCollection | Collection of TaskTypeItem Items. |
| TaskTypeItem | Individual type definition for identifying a kind of project or task. |
| TicketCollectionConverterT | Serializes and deserializes a property representing a collection of items that inherit from the BaseItem object. |
| TicketConverterT | Serializes and deserializes a property reference using its Ticket. |
| TimeBlockCollection | Collection of TimeBlockItem Items. |
| TimeBlockItem | Information about a reusable block of time entries. |
| TimeNotationCollection | Collection of TimeNotationItem Items. |
| TimeNotationDateCollection | Collection of TimeNotationDateItem Items. |
| TimeNotationDateItem | Tracking information for a time notation and an individual resolved date range. |
| TimeNotationItem | Information expressing a singular scope of time. |
| TimerCollection | Collection of TimerItem Items. |
| TimerItem | Information about an individual timer. |
| IItem | Interface for a generic data item. |
| BudgetStatusEnum | Enumeration of known budget states. |
| BudgetTypeEnum | Enumeration of known budget resource types. |
| DependencyTypeEnum | Enumeration of the known project and task dependency types. |
| OrganizationRelationType | Enumeration of types of relationship another organization might have to this one. |
| ProjectTaskStateEnum | Enumeration of the basic task system states. |
| ProjectTaskTypeEnum | Enumeration of all of the available system types for a project or task. |
| RangePartEnum | Enumeration of Parts of a Range. |
| ScheduleActivePeriod | Enumeration of occurrence limits for repeated times. |
| ScheduleMonth | Combinatorial enumeration of months. |
| ScheduleRepetitionRate | Enumeration of scopes of repetition. |
| ScheduleWeekDay | Combinatorial enumeration of days of the week. |
| ScheduleWeekOrdinal | Enumeration of ordinal week-based scopes for month activities. |
| TelephoneTypeEnum | Enumeration of recognized telephone types. |
| TimeEstimateType | Enumeration of the known types of time and date estimation. |