Visual C++ and MFC Programming 2nd Edition

Chapter 5: The Document/View Architecture Visual C++ and MFC Fundamentals

BEGIN_MESSAGE_MAP(CTestDoc, CDocument)

ON_COMMAND(ID_FILE_SEND_MAIL, OnFileSendMail)

ON_UPDATE_COMMAND_UI(ID_FILE_SEND_MAIL, OnUpdateFileSendMail)

END_MESSAGE_MAP

Once a user has finished using a document, he or she would need to close it, which is

done by either clicking the System Close button or using the main menu (File -> Exit). If

the user clicks the System Close button , the application would need to close the frame.

At this time, the document would call the OnCloseDocument() method. Its syntax is:

virtual void OnCloseDocument();

You can use this method (which really behave as an event) to decide what to do before a

frame is closed.

When the user decides to close an application, the document class checks the file to know

whether the file is "dirty". If the file is dirty, you may want to ask the user to save or not

save the document. As we saw earlier with the ID_APP_EXIT pre-configured menu, the

framework can check this setting for you. Also, while using a file, the user may want to

save it. If the user is working on a document that was opened from a drive, the document

may be saved immediately behind the scenes. If the user is working on a brand new

document and decides to save it, you may want to check first if this is possible and what

needs to be done in order to save the document.

To help the user save a document, you can create a menu item. Using the

Document/View architecture, add a menu item with the identifier ID_FILE_SAVE in the

IDR_MAINFRAME common resource name. It is that simple. This menu is usually

positioned under File with a caption of &Save.

If the user wants to save a document with a different name and/or a different location,

which is usually done by clicking File -> Save As... from the main menu, create a menu

item with the ID_FILE_SAVE_AS identifier. This menu item is usually placed under

Save in the File main menu. If the user is working on a new document (that has not been

saved previously), or if the user working on a document that is marked as Read-Only, or

if the user decides to close the application after working on a new document, and if the

user decides to save the document, the action would initiate the File -> Save As action.

When the user has decided to save a document, if the document is dirty, a message box

would display to the user for a decision. If the user decides to save the document, the

CDocument class provides the OnSaveDocument() method to validate the action. The

syntax of this method is:

virtual BOOL OnSaveDocument(LPCTSTR lpszPathName);

To save a document, the user must specify where the document would reside. This is

communicated as the lpszPathName argument). In reality, as its name suggests, this

method is not used to save a document. It allows you to validate the action or desire to

save a document. For example, if the user clicks File -> Save on the main menu or if the

user is attempting to close a dirty document, you can use this method to check what is

going or to deny saving the file.

Serialization is the ability to store data on a drive. Therefore, to actually save a file, the

CObject class provides the Serialize() method to its children. To store data of the file, its

information is held by a class called CArchive. When saving a file, a CArchive object is

passed to the Serialize method as reference, which modifies its value.