The CGraphDoc class is an extension of CDocument that has an SRGraph member variable. It also has a Serialize() function that saves and restores the graph object.

In addition, CGraphDoc supports Objective Chart’s Communication Document system. This system, which is described briefly below and in more detail in Chapter 20, “Communication Document System,” allows CGraphDoc documents to communicate with other documents in the application, even those of another document type.

As illustrated in Chapter 4, “Fast Start With Objective Chart,” simply changing the base class of the document class created by AppWizard from CDocument to CGraphDoc provides a ready-made SRGraph object, m_Graph.