How To: Use Project Context

These notes provide a brief description of the ProjectContext class' purpose.

For many people working with MPXJ, the main concern is reading a single project and working with the data it contains. In fact most of the file formats supported by MPXJ can only contain a single project. In this case you will just need to work with a ProjectFile instance, which provides access to all of the components of the project, as illustrated by the simplified diagram below:

graph LR
    ProjectFile(ProjectFile)
    Configuration(Configuration)
    Properties(Properties)
    CodeDefinitions(Code Definitions)
    FieldDefinitions(Field Definitions)
    Calendars(Calendars)
    Resources(Resources)
    Tasks(Tasks)
    Relations(Relations)
    ResourceAssignments(Resource Assignments) 
    ProjectFile --> Configuration
    ProjectFile --> Properties
    ProjectFile --> CodeDefinitions
    ProjectFile --> FieldDefinitions
    ProjectFile --> Calendars
    ProjectFile --> Resources
    ProjectFile --> Tasks
    ProjectFile --> Relations
    ProjectFile --> ResourceAssignments

For applications and file formats which support multiple projects (at the time of writing Primavera P6 databases, XER files and PMXML files) the you can still use a ProjectFile instance and work with the data shown above, however behind the scenes the data you are working with is actually stored differently, as the simplified diagram below illustrates:

graph LR
    ProjectContext(ProjectContext)
    CodeDefinitions(Code Definitions)
    FieldDefinitions(Field Definitions)
    Calendars(Calendars)
    Projects(Projects)
    Resources(Resources)
    Configuration(Configuration)
    ProjectFiles(ProjectFile)
    Properties(Properties)
    Tasks(Tasks)
    Relations(Relations)
    ResourceAssignments(Resource Assignments)
    ProjectContext --> CodeDefinitions
    ProjectContext --> FieldDefinitions
    ProjectContext --> Calendars
    ProjectContext --> Projects
    ProjectContext --> Resources
    ProjectContext --> Configuration
    Projects --> ProjectFiles
    ProjectFiles --> Properties
    ProjectFiles --> Tasks
    ProjectFiles --> Relations
    ProjectFiles --> ResourceAssignments

The ProjectContext class is used as a container for all common data shared across projects (calendars, resources, code definitions and so on). Most of the time you don't need to be aware of the ProjectContext class, but it is useful to understand that when reading, for example, an XER file containing multiple projects, all the resources, calendars and so on are actually stored as part of the ProjectContext, even if you retrieve that data via a ProjectFile instance.