深入浅出MFC文档/视图架构之文档模板

2.文档模板类CDocTemplate

　　文档模板类CDocTemplate是一个抽象基类（这意味着不能直接用它来定义对象而必须用它的派生类），它定义了文档模板的基本处理函数接口。对一个单文档界面程序，需使用单文档模板类CSingleDocTemplate，而对于一个多文档界面程序，需使用多文档模板类CMultipleDocTemplate。我们首先来看看CDocTemplate类的声明：

class CDocTemplate : public CCmdTarget { 　DECLARE_DYNAMIC(CDocTemplate) 　// Constructors 　protected: 　　CDocTemplate(UINT nIDResource, CRuntimeClass* pDocClass, CRuntimeClass* pFrameClass, CRuntimeClass* pViewClass); 　public: 　　virtual void LoadTemplate(); 　　// Attributes 　public: 　　// setup for OLE containers 　　void SetContainerInfo(UINT nIDOleInPlaceContainer); 　　// setup for OLE servers 　　void SetServerInfo(UINT nIDOleEmbedding, UINT nIDOleInPlaceServer = 0, CRuntimeClass* pOleFrameClass = NULL, CRuntimeClass* pOleViewClass = NULL); 　　// iterating over open documents 　　virtual POSITION GetFirstDocPosition() const = 0; 　　virtual CDocument* GetNextDoc(POSITION& rPos) const = 0; 　　// Operations 　public: 　　virtual void AddDocument(CDocument* pDoc); // must override 　　virtual void RemoveDocument(CDocument* pDoc); // must override 　　enum DocStringIndex 　　{ 　　　windowTitle, // default window title 　　　docName, // user visible name for default document 　　　fileNewName, // user visible name for FileNew 　　　// for file based documents: 　　　filterName, // user visible name for FileOpen 　　　filterExt, // user visible extension for FileOpen 　　　// for file based documents with Shell open support: 　　　regFileTypeId, // REGEDIT visible registered file type identifier 　　　regFileTypeName, // Shell visible registered file type name 　　}; 　　virtual BOOL GetDocString(CString& rString, enum DocStringIndex index) const; // get one of the info strings 　　CFrameWnd* CreateOleFrame(CWnd* pParentWnd, CDocument* pDoc,BOOL bCreateView); 　　// Overridables 　public: 　　enum Confidence 　　{ 　　　noAttempt, 　　　maybeAttemptForeign, 　　　maybeAttemptNative, 　　　yesAttemptForeign, 　　　yesAttemptNative, 　　　yesAlreadyOpen 　　}; 　　virtual Confidence MatchDocType(LPCTSTR lpszPathName,CDocument*& rpDocMatch); 　　virtual CDocument* CreateNewDocument(); 　　virtual CFrameWnd* CreateNewFrame(CDocument* pDoc, CFrameWnd* pOther); 　　virtual void InitialUpdateFrame(CFrameWnd* pFrame, CDocument* pDoc,BOOL bMakeVisible = TRUE); 　　virtual BOOL SaveAllModified(); // for all documents 　　virtual void CloseAllDocuments(BOOL bEndSession); 　　virtual CDocument* OpenDocumentFile( 　　　LPCTSTR lpszPathName, BOOL bMakeVisible = TRUE) = 0; 　　　// open named file 　　　// if lpszPathName == NULL => create new file with this type 　　virtual void SetDefaultTitle(CDocument* pDocument) = 0; 　　// Implementation 　public: 　　BOOL m_bAutoDelete; 　　virtual ~CDocTemplate(); 　　// back pointer to OLE or other server (NULL if none or disabled) 　　CObject* m_pAttachedFactory; 　　// menu & accelerator resources for in-place container 　　HMENU m_hMenuInPlace; 　　HACCEL m_hAccelInPlace; 　　// menu & accelerator resource for server editing embedding 　　HMENU m_hMenuEmbedding; 　　HACCEL m_hAccelEmbedding; 　　// menu & accelerator resource for server editing in-place 　　HMENU m_hMenuInPlaceServer; 　　HACCEL m_hAccelInPlaceServer; 　　#ifdef _DEBUG 　　　virtual void Dump(CDumpContext&) const; 　　　virtual void AssertValid() const; 　　#endif 　　virtual void OnIdle(); // for all documents 　　virtual BOOL OnCmdMsg(UINT nID, int nCode, void* pExtra,AFX_CMDHANDLERINFO* pHandlerInfo); 　protected: 　　UINT m_nIDResource; // IDR_ for frame/menu/accel as well 　　UINT m_nIDServerResource; // IDR_ for OLE inplace frame/menu/accel 　　UINT m_nIDEmbeddingResource; // IDR_ for OLE open frame/menu/accel 　　UINT m_nIDContainerResource; // IDR_ for container frame/menu/accel 　　CRuntimeClass* m_pDocClass; // class for creating new documents 　　CRuntimeClass* m_pFrameClass; // class for creating new frames 　　CRuntimeClass* m_pViewClass; // class for creating new views 　　CRuntimeClass* m_pOleFrameClass; // class for creating in-place frame 　　CRuntimeClass* m_pOleViewClass; // class for creating in-place view 　　CString m_strDocStrings; // '\n' separated names 　　// The document names sub-strings are represented as _one_ string: 　　// windowTitle\ndocName\n ... (see DocStringIndex enum) };

　　文档模板挂接了后面要介绍的文档、视图和框架窗口，使得它们得以互相关联。通过文档模板，程序确定了创建或打开一个文档时，以什么样的视图和框架窗口来显示。文档模板依靠保存相互对应的文档、视图和框架窗口的CRuntimeClass对象指针来实现上述挂接，这就是文档模板类中的成员变量m_pDocClass、m_pFrameClass、m_pViewClass的由来。实际上，对m_pDocClass、m_pFrameClass、m_pViewClass的赋值在CDocTemplate类的构造函数中实施：

CDocTemplate::CDocTemplate(UINT nIDResource, CRuntimeClass* pDocClass, CRuntimeClass* pFrameClass, CRuntimeClass* pViewClass) { 　ASSERT_VALID_IDR(nIDResource); 　ASSERT(pDocClass == NULL || pDocClass->IsDerivedFrom(RUNTIME_CLASS(CDocument))); 　ASSERT(pFrameClass == NULL ||pFrameClass->IsDerivedFrom(RUNTIME_CLASS(CFrameWnd))); 　ASSERT(pViewClass == NULL || pViewClass->IsDerivedFrom(RUNTIME_CLASS(CView))); 　m_nIDResource = nIDResource; 　m_nIDServerResource = NULL; 　m_nIDEmbeddingResource = NULL; 　m_nIDContainerResource = NULL; 　m_pDocClass = pDocClass; 　m_pFrameClass = pFrameClass; 　m_pViewClass = pViewClass; 　m_pOleFrameClass = NULL; 　m_pOleViewClass = NULL; 　m_pAttachedFactory = NULL; 　m_hMenuInPlace = NULL; 　m_hAccelInPlace = NULL; 　m_hMenuEmbedding = NULL; 　m_hAccelEmbedding = NULL; 　m_hMenuInPlaceServer = NULL; 　m_hAccelInPlaceServer = NULL; 　// add to pStaticList if constructed as static instead of on heap 　if (CDocManager::bStaticInit) 　{ 　　m_bAutoDelete = FALSE; 　　if (CDocManager::pStaticList == NULL) 　　　CDocManager::pStaticList = new CPtrList; 　　if (CDocManager::pStaticDocManager == NULL) 　　　CDocManager::pStaticDocManager = new CDocManager; 　　　CDocManager::pStaticList->AddTail(this); 　} 　else 　{ 　　m_bAutoDelete = TRUE; // usually allocated on the heap 　　LoadTemplate(); 　} }

　　文档模板类CDocTemplate还保存了它所支持的全部文档类的信息，包括所支持文档的文件扩展名、文档在框架窗口中的名字、图标等。