- Table of Contents
- Copyright
- About the Authors
- About the Contributors
- Acknowledgments
- Tell Us What You Think!
- Introduction
- How to Use This Book
- What You Need to Use This Book
- What's New in Visual C++ 6.0
- Contacting the Main Author
- Part I: Introduction
- Chapter 1. The Visual C++ 6.0 Environment
- Part II: MFC Programming
- Chapter 2. MFC Class Library Overview
- Chapter 3. MFC Message Handling Mechanism
- Chapter 4. The Document View Architecture
- Chapter 5. Creating and Using Dialog Boxes
- Chapter 6. Working with Device Contexts and GDI Objects
- Chapter 7. Creating and Using Property Sheets
- Chapter 8. Working with the File System
- Chapter 9. Using Serialization with File and Archive Objects
- Part III: Internet Programming with MFC
- Chapter 10. MFC and the Internet Server API (ISAPI)
- Chapter 11. The WinInet API
- Chapter 12. MFC HTML Support
- Part IV: Advanced Programming Topics
- Chapter 13. Using the Standard C++ Library
- Chapter 14. Error Detection and Exception Handling Techniques
- Chapter 15. Debugging and Profiling Strategies
- Chapter 16. Multithreading
- Chapter 17. Using Scripting and Other Tools to Automate the Visual C++ IDE
- Part V: Database Programming
- Chapter 18. Creating Custom AppWizards
- Chapter 19. Database Overview
- Chapter 20. ODBC Programming
- Chapter 21. MFC Database Classes
- Chapter 22. Using OLE DB
- Chapter 23. Programming with ADO
- Part VI: MFC Support for COM and ActiveX
- Chapter 24. Overview of COM and Active Technologies
- Chapter 25. Active Documents
- Chapter 26. Active Containers
- Chapter 27. Active Servers
- Chapter 28. ActiveX Controls
- Part VII: Using the Active Template Library
- Chapter 29. ATL Architecture
- Chapter 30. Creating COM Objects Using ATL
- Chapter 31. Creating ActiveX Controls Using ATL
- Chapter 32. Using ATL to Create MTS and COM+ Components
- Part VIII: Finishing Touches
- Chapter 33. Adding Windows Help
- Part IX: Appendix
The COM Interfaces
Nine COM interfaces are part of the active document container specification. Six of these interfaces were part of the OLE container specification, and the other three are new to active document containers. Two of the new interfaces—IOleCommandTarget and IContinueCallback—are optional. Table 26.1 lists the COM interfaces with the corresponding MFCs that implement the interface.
Table 26.1. COM Interfaces Used By Containers
| COM Interface | Type | MFC |
| IOleInPlaceFrame | OLE 2.0 | COleControlContainer |
| IOleCommandTarget | New, optional | None |
| IOleInPlaceUIWindow | OLE 2.0 | COleControlContainer |
| IOleContainer | OLE 2.0 | COleControlContainer |
| IOleClientSite | OLE 2.0 | COleClientItem |
| IAdviseSink | OLE 2.0 | COleClientItem |
| IOleDocumentSite | New, required | None |
| IOleInPlaceSite | OLE 2.0 | COleClientItem |
| IContinueCallback | New, optional | None |
This section discusses these interfaces in more detail.
IOleInPlaceFrame
IOleInPlaceFrame is a COM interface derived from three other COM interfaces: IOleInPlaceUIWindow, IOleWindow, and IUnknown. IOleInPlaceFrame controls the top-level frame window of the container. With this interface, it is possible to add and remove items from the composite menu, set status text, manage modeless dialog boxes, and translate accelerator keys. Each of the interfaces that IOleInPlaceFrame derives from contributes required methods. Table 26.2 describes these interfaces.
Table 26.2. IOleInPlaceFrame Interfaces
| Interface | Description |
| IUnknown Methods | |
| AddRef | Adds a reference count to the object |
| QueryInterface | Discovers required interfaces |
| Release | Decrements the reference count for the object and eventually deletes the object |
| IOleWindow Methods | |
| ContextSensitiveHelp | Gives the container the opportunity to handle context-sensitive help |
| GetWindow | Gets the window handle to the frame, document, parent, or in-place object |
| IOleInPlaceUIWindow Methods | |
| GetBorder | Returns the rectangle where ActiveX documents can put their toolbars and other controls |
| RequestBorderSpace | Asks the container for space for toolbars and other controls |
| SetBorderSpace | Tells the container to allocate the space for toolbars and other controls |
| IOleInPlaceUIWindow Methods | |
| SetActiveObject | Called by the ActiveX document to create a link between itself and the active document container |
| IOleInPlaceFrame Methods | |
| EnableModeless | Enables or disables modeless dialog boxes at the frame level |
| InsertMenus | Allows the container to insert its menu items into the shared menu |
| RemoveMenus | Allows the container to remove its menu items |
| SetMenu | Allows the ActiveX document to install the merged container/document menu |
| SetStatusText | Displays status text in the static area |
| TranslateAccelerator | Translates accelerator keystrokes intended for the container |
IOleCommandTarget
IOleCommandTarget allows client and server to dispatch commands to each other. With the active document container, IOleCommandTarget allows the active document to route commands that it generates to the container. Table 26.3 describes the interfaces.
Table 26.3. IOleCommandTarget Interfaces
| Interface | Description |
| IUnknown Methods | |
| AddRef | Adds a reference count to the object |
| QueryInterface | Discovers required interfaces |
| Release | Decrements the reference count for the object and eventually deletes the object |
| IOleCommandTarget Methods | |
| Exec | Executes the requested command |
| QueryStatus | Asks the object whether it supports a particular type of command |
IOleInPlaceUIWindow
IOleInPlaceUIWindow allows active documents to negotiate border space in the frame window. The interface manages the allocation of border space and the interaction between the document and the frame. IOleInPlaceUIWindow derives from IOleWindow. Table 26.4 describes the interfaces.
Table 26.4. IOleInPlaceUIWindow Interfaces
| Interface | Description |
| IUnknown Interfaces | |
| AddRef | Adds a reference count to the object |
| QueryInterface | Discovers required interfaces |
| Release | Decrements the reference count for the object and eventually deletes the object |
| IOleWindow Interfaces | |
| ContextSensitiveHelp | Gives the container the opportunity to handle context-sensitive help |
| GetWindow | Gets the window handle to the frame, document, parent, or in-place object |
| IOleInPlaceUIWindow Methods | |
| GetBorder | Returns the rectangle where ActiveX documents can put their toolbars and other controls |
| RequestBorderSpace | Asks the container for space for toolbars and other controls |
| SetActiveObject | Called by the ActiveX document to create a link between itself and the active document container |
| SetBorderSpace | Tells the container to allocate the space for toolbars and other controls |
IOleContainer
IOleContainer queries objects in a compound document or locks the container in the running state. This interface is useful only when the container supports linked objects and requires both the container and the document to implement it. Table 26.5 describes the interfaces.
Table 26.5. IOleContainer Interfaces
| Interface | Description |
| IUnknown Interfaces | |
| AddRef | Adds a reference count to the object |
| QueryInterface | Discovers required interfaces |
| Release | Decrements the reference count for the object and eventually deletes the object |
| IParseDisplayName Methods | |
| ParseDisplayName | Parses a display name into something usable by a moniker |
| IOleContainer Methods | |
| EnumObjects | Enumerates objects in the container |
| LockContainer | Keeps the container locked in running mode until it is explicitly released |
IOleClientSite
IOleClientSite helps an active document get information about its container environment. It can get information about its display area as well as other user interface information from the container. Table 26.6 describes the interfaces.
Table 26.6. IOleClientSite Interfaces
| Interface | Description |
| IUnknown Interfaces | |
| AddRef | Adds a reference count to the object |
| QueryInterface | Discovers required interfaces |
| Release | Decrements the reference count for the object and eventually deletes the object |
| IOleClientSite Methods | |
| GetContainer | Returns a pointer to the container's IOleContainer interface |
| GetMoniker | Creates a moniker to access the embedded active document |
| OnShowWindow | Notifies the container when an object is about to become visible or invisible; does not apply to active documents or other in-place activated objects |
| IOleClientSite Methods | |
| RequestNewObjectLayout | Asks the container to provide more or less space for displaying the active document |
| SaveObject | Saves the active document associated with this site |
| ShowObject | Positions the active document so that it is visible to the user; makes sure the container itself is visible to the user |
IAdviseSink
IAdviseSink provides a way for active documents to notify their containers when their data or states change. Table 26.7 describes the interfaces.
Table 26.7. IAdviseSink Interfaces
| Interface | Description |
| IUnknown Interfaces | |
| AddRef | Adds a reference count to the object |
| QueryInterface | Discovers required interfaces |
| Release | Decrements the reference count for the object and eventually deletes the object |
| IAdviseSink Methods | |
| OnClose | Called when the active document has been closed |
| OnDataChange | Called when the data has changed |
| OnRename | Called when the name has changed |
| OnSave | Called when the active document has been saved to disk |
| OnViewChange | Called when the view has changed |
IOleDocumentSite
IOleDocumentSite allows an active document to bypass the normal activation sequence for an in-place object and activate directly as a document object. Table 26.8 describes the interfaces.
Table 26.8. IOleDocumentSite Interfaces
| Interface | Description |
| IUnknown Interfaces | |
| AddRef | Adds a reference count to the object |
| QueryInterface | Discovers required interfaces |
| Release | Decrements the reference count for the object and eventually deletes the object |
| IOleDocumentSite Methods | |
| ActivateMe | Actives the active document as a document object instead of an in-place object |
IOleInPlaceSite
IOleInPlaceSite works with IOleDocumentSite. For each view an active document instantiates, an IOleInPlaceSite object must exist. IOleDocumentSite manages one or more IOleInPlaceSite objects. The IOleInPlaceSite interface provides methods that manage the active document. Table 26.9 describes the interfaces.
Table 26.9. IOleInPlaceSite Interfaces
| Interface | Description |
| IUnknown Interfaces | |
| AddRef | Adds a reference count to the object |
| QueryInterface | Discovers required interfaces |
| Release | Decrements the reference count for the object and eventually deletes the object |
| IOleWindow Methods | |
| ContextSensitiveHelp | Gives the container the opportunity to handle context-sensitive help |
| GetWindow | Gets the window handle to the frame, document, parent, or in-place object |
| IOleInPlaceSite Methods | |
| CanInPlaceActivate | Gives the object permission to in-place activate |
| DeactivateAndUndo | Tells the container to end the in-place active session and return to its Undo state |
| DiscardUndoState | Tells the container to discard its Undo state |
| IOleInPlaceSite Methods | |
| GetWindowContext | Provides window hierarchy information |
| OnInPlaceActivate | Notifies the container that the ActiveX document is about to in-place activate |
| OnInPlaceDeactivate | Tells the container that the ActiveX document is no longer in-place active |
| OnPosRectChange | Used by the active document to tell the container that its size has changed |
| OnUIActivate | Called when the active document is about to in-place activate and replace the menu with a composite menu |
| OnUIDeactivate | Tells the container that the ActiveX document is going away and that the container should restore its user interface |
| Scroll | Tells the container how to scroll the object |
IContinueCallback
IContinueCallback helps the active document ask the container whether it should continue an interruptible process. This feature is used with the active document's IPrint interface. Table 26.10 describes the interfaces.
Table 26.10. IContinueCallback Interfaces
| Interface | Description |
| IUnknown Interfaces | |
| AddRef | Adds a reference count to the object |
| QueryInterface | Discovers required interfaces |
| Release | Decrements the reference count for the object and eventually deletes the object |
| IContinueCallback Methods | |
| FContinue | Used by printing tasks to determine whether printing should continue |
| FContinuePrinting | Used by the printing tasks to determine whether the task should continue; also provides some progress information |
You can find more information about these COM interfaces in the Visual C++ Help system. The system also provides good background information on the world of COM, OLE, and other Active technologies. Another interesting exercise is to search through the MFC source code to see where Microsoft has implemented these and other COM interfaces in the MFC Library. The MFC source code is located in the \Vc98\Mfc subdirectory.
Building an Active Document Container | Next Section
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