MFC 程序来龙去脉_子文档 4
MFC 程序来龙去脉_子文档 4
探究 pThread->InitInstance()
由上面解释可知 pThread 指向 theApp 。尽管类型不是CFirstMFCDemoApp* ，但必定是其父类。由 OO 多态性可知该语句调用的是子类方法 CFirstMFCDemoApp::InitInstance()。
查看 CFirstMFCDemoApp::InitInstance() 源码：
BOOL CFirstMFCDemoApp::InitInstance()
{
// 如果一个运行在Windows XP 上的应用程序清单指定要
// 使用ComCtl32.dll 版本6 或更高版本来启用可视化方式，
//则需要InitCommonControlsEx()。否则，将无法创建窗口。
INITCOMMONCONTROLSEX InitCtrls;
InitCtrls.dwSize = sizeof(InitCtrls);
// 将它设置为包括所有要在应用程序中使用的
// 公共控件类。
InitCtrls.dwICC = ICC_WIN95_CLASSES;
InitCommonControlsEx(&InitCtrls);
CWinApp::InitInstance();
// 初始化OLE 库
if (!AfxOleInit())
{
AfxMessageBox(IDP_OLE_INIT_FAILED);
return FALSE;
}
AfxEnableControlContainer();
// 标准初始化
// 如果未使用这些功能并希望减小
// 最终可执行文件的大小，则应移除下列
// 不需要的特定初始化例程
// 更改用于存储设置的注册表项
// TODO: 应适当修改该字符串，
// 例如修改为公司或组织名
SetRegistryKey(_T("应用程序向导生成的本地应用程序"));
LoadStdProfileSettings(4); // 加载标准INI 文件选项(包括MRU)
// 注册应用程序的文档模板。文档模板
// 将用作文档、框架窗口和视图之间的连接
CSingleDocTemplate* pDocTemplate;
pDocTemplate = new CSingleDocTemplate(
IDR_MAINFRAME,
RUNTIME_CLASS(CFirstMFCDemoDoc),
RUNTIME_CLASS(CMainFrame), // 主SDI 框架窗口
RUNTIME_CLASS(CFirstMFCDemoView));
if (!pDocTemplate)
return FALSE;
AddDocTemplate(pDocTemplate);
// 分析标准外壳命令、DDE、打开文件操作的命令行
CCommandLineInfo cmdInfo;
ParseCommandLine(cmdInfo);
// 调度在命令行中指定的命令。如果
// 用/RegServer、/Register、/Unregserver 或/Unregister 启动应用程序，则返回FALSE。
if (!ProcessShellCommand(cmdInfo))
return FALSE;
// 唯一的一个窗口已初始化，因此显示它并对其进行更新
m_pMainWnd->ShowWindow(SW_SHOW);
m_pMainWnd->UpdateWindow();
// 仅当具有后缀时才调用DragAcceptFiles
// 在SDI 应用程序中，这应在ProcessShellCommand 之后发生
return TRUE;
}
由
m_pMainWnd->ShowWindow(SW_SHOW);
m_pMainWnd->UpdateWindow();
两行代码可知：InitInstance 实现了窗口的显示和更新。但是窗口尚未注册和创建，并且 m_pMainWnd 尚未初始化。
我们看看 pFrame 到底是个什么，它干了什么事情。
查看CSingDocTemplate::OpenDocumentFile() 源码（C:\Program Files\Microsoft Visual Studio 9.0\VC\atlmfc\src\mfc\docsingl.cpp）：
CDocument* CSingleDocTemplate::OpenDocumentFile(LPCTSTR lpszPathName,
BOOL bMakeVisible)
// if lpszPathName == NULL => create new file of this type
{
CDocument* pDocument = NULL;
CFrameWnd* pFrame = NULL;
BOOL bCreated = FALSE; // => doc and frame created
BOOL bWasModified = FALSE;
if (m_pOnlyDoc != NULL)
{
// already have a document - reinit it
pDocument = m_pOnlyDoc;
if (!pDocument->SaveModified())
return NULL; // leave the original one
pFrame = (CFrameWnd*)AfxGetMainWnd();
ASSERT(pFrame != NULL);
ASSERT_KINDOF(CFrameWnd, pFrame);
ASSERT_VALID(pFrame);
}
else
{
// create a new document
pDocument = CreateNewDocument();
ASSERT(pFrame == NULL); // will be created below
bCreated = TRUE;
}
if (pDocument == NULL)
{
AfxMessageBox(AFX_IDP_FAILED_TO_CREATE_DOC);
return NULL;
}
ASSERT(pDocument == m_pOnlyDoc);
if (pFrame == NULL)
{
ASSERT(bCreated);
// create frame - set as main document frame
BOOL bAutoDelete = pDocument->m_bAutoDelete;
pDocument->m_bAutoDelete = FALSE;
// don't destroy if something goes wrong
pFrame = CreateNewFrame(pDocument, NULL);
pDocument->m_bAutoDelete = bAutoDelete;
if (pFrame == NULL)
{
AfxMessageBox(AFX_IDP_FAILED_TO_CREATE_DOC);
delete pDocument; // explicit delete on error
return NULL;
}
}
if (lpszPathName == NULL)
{
// create a new document
SetDefaultTitle(pDocument);
// avoid creating temporary compound file when starting up invisible
if (!bMakeVisible)
pDocument->m_bEmbedded = TRUE;
if (!pDocument->OnNewDocument())
{
// user has been alerted to what failed in OnNewDocument
TRACE(traceAppMsg, 0, "CDocument::OnNewDocument returned FALSE.\n");
if (bCreated)
pFrame->DestroyWindow(); // will destroy document
return NULL;
}
}
else
{
CWaitCursor wait;
// open an existing document
bWasModified = pDocument->IsModified();
pDocument->SetModifiedFlag(FALSE); // not dirty for open
if (!pDocument->OnOpenDocument(lpszPathName))
{
// user has been alerted to what failed in OnOpenDocument
TRACE(traceAppMsg, 0, "CDocument::OnOpenDocument returned FALSE.\n");
if (bCreated)
{
pFrame->DestroyWindow(); // will destroy document
}
else if (!pDocument->IsModified())
{
// original document is untouched
pDocument->SetModifiedFlag(bWasModified);
}
else
{
// we corrupted the original document
SetDefaultTitle(pDocument);
if (!pDocument->OnNewDocument())
{
TRACE(traceAppMsg, 0, "Error: OnNewDocument failed after trying "
"to open a document - trying to continue.\n");
// assume we can continue
}
}
return NULL; // open failed
}
pDocument->SetPathName(lpszPathName);
}
CWinThread* pThread = AfxGetThread();
ASSERT(pThread);
if (bCreated && pThread->m_pMainWnd == NULL)
{
// set as main frame (InitialUpdateFrame will show the window)
pThread->m_pMainWnd = pFrame;
}
InitialUpdateFrame(pFrame, pDocument, bMakeVisible);
return pDocument;
}
（1）分析语句 pFrame = (CFrameWnd*)AfxGetMainWnd(); 没有找到AfxGetMainWnd()源码。网上说：“返回主框架的指针”。也就是 m_pMainWnd。
（2）分析语句 pFrame = CreateNewFrame(pDocument, NULL); 查看CDocTemplate::CreateNewFrame 源码：
CFrameWnd* CDocTemplate::CreateNewFrame(CDocument* pDoc, CFrameWnd* pOther)
{
if (pDoc != NULL)
ASSERT_VALID(pDoc);
// create a frame wired to the specified document
ASSERT(m_nIDResource != 0); // must have a resource ID to load from
CCreateContext context;
context.m_pCurrentFrame = pOther;
context.m_pCurrentDoc = pDoc;
context.m_pNewViewClass = m_pViewClass;
context.m_pNewDocTemplate = this;
if (m_pFrameClass == NULL)
{
TRACE(traceAppMsg, 0, "Error: you must override CDocTemplate::CreateNewFrame.\n");
ASSERT(FALSE);
return NULL;
}
CFrameWnd* pFrame = (CFrameWnd*)m_pFrameClass->CreateObject();
if (pFrame == NULL)
{
TRACE(traceAppMsg, 0, "Warning: Dynamic create of frame %hs failed.\n",
m_pFrameClass->m_lpszClassName);
return NULL;
}
ASSERT_KINDOF(CFrameWnd, pFrame);
if (context.m_pNewViewClass == NULL)
TRACE(traceAppMsg, 0, "Warning: creating frame with no default view.\n");
// create new from resource
if (!pFrame->LoadFrame(m_nIDResource,
WS_OVERLAPPEDWINDOW | FWS_ADDTOTITLE, // default frame styles
NULL, &context))
{
TRACE(traceAppMsg, 0, "Warning: CDocTemplate couldn't create a frame.\n");
// frame will be deleted in PostNcDestroy cleanup
return NULL;
}
// it worked !
return pFrame;
}
分析语句：
CFrameWnd* pFrame =
(CFrameWnd*)m_pFrameClass->CreateObject();
m_pFrameClass类型为CRuntimeClass* ，方法CreateObject() 创建了一个CFrameWnd对象（等效于 pFrame = new CFrameWnd()）。
分析语句：
!pFrame->LoadFrame(m_nIDResource,
WS_OVERLAPPEDWINDOW | FWS_ADDTOTITLE, // default frame styles
NULL, &context);
查看 CFrameWnd::LoadFrame 源码：
BOOL CFrameWnd::LoadFrame(UINT nIDResource, DWORD dwDefaultStyle,
CWnd* pParentWnd, CCreateContext* pContext)
{
// only do this once
ASSERT_VALID_IDR(nIDResource);
ASSERT(m_nIDHelp == 0 || m_nIDHelp == nIDResource);
m_nIDHelp = nIDResource; // ID for help context (+HID_BASE_RESOURCE)
CString strFullString;
if (strFullString.LoadString(nIDResource))
AfxExtractSubString(m_strTitle, strFullString, 0); // first sub-string
VERIFY(AfxDeferRegisterClass(AFX_WNDFRAMEORVIEW_REG));
// attempt to create the window
LPCTSTR lpszClass = GetIconWndClass(dwDefaultStyle, nIDResource);
CString strTitle = m_strTitle;
if (!Create(lpszClass, strTitle, dwDefaultStyle, rectDefault,
pParentWnd, ATL_MAKEINTRESOURCE(nIDResource), 0L, pContext))
{
return FALSE; // will self destruct on failure normally
}
// save the default menu handle
ASSERT(m_hWnd != NULL);
m_hMenuDefault = m_dwMenuBarState == AFX_MBS_VISIBLE ? ::GetMenu(m_hWnd) : m_hMenu;
// load accelerator resource
LoadAccelTable(ATL_MAKEINTRESOURCE(nIDResource));
if (pContext == NULL) // send initial update
SendMessageToDescendants(WM_INITIALUPDATE, 0, 0, TRUE, TRUE);
return TRUE;
}
终于见到我们想要的窗口注册和创建代码：
AfxDeferRegisterClass(AFX_WNDFRAMEORVIEW_REG))
!Create(lpszClass, strTitle, dwDefaultStyle, rectDefault,
pParentWnd, ATL_MAKEINTRESOURCE(nIDResource), 0L, pContext)
继续看看做了哪些事情吧!
（1）查看AfxDeferRegisterClass()源码（C:\Program Files\Microsoft Visual Studio 9.0\VC\atlmfc\src\mfc\afximpl.h）：
#define AfxDeferRegisterClass(fClass) \
AfxEndDeferRegisterClass(fClass)
BOOL AFXAPI AfxEndDeferRegisterClass(LONG fToRegister)
{
// mask off all classes that are already registered
AFX_MODULE_STATE* pModuleState = AfxGetModuleState();
fToRegister &= ~pModuleState->m_fRegisteredClasses;
if (fToRegister == 0)
return TRUE;
LONG fRegisteredClasses = 0;
// common initialization
WNDCLASS wndcls;
memset(&wndcls, 0, sizeof(WNDCLASS)); // start with NULL defaults
wndcls.lpfnWndProc = DefWindowProc;
wndcls.hInstance = AfxGetInstanceHandle();
wndcls.hCursor = afxData.hcurArrow;
INITCOMMONCONTROLSEX init;
init.dwSize = sizeof(init);
// work to register classes as specified by fToRegister, populate fRegisteredClasses as we go
if (fToRegister & AFX_WND_REG)
{
// Child windows - no brush, no icon, safest default class styles
wndcls.style = CS_DBLCLKS | CS_HREDRAW | CS_VREDRAW;
wndcls.lpszClassName = _afxWnd;
if (AfxRegisterClass(&wndcls))
fRegisteredClasses |= AFX_WND_REG;
}
if (fToRegister & AFX_WNDOLECONTROL_REG)
{
// OLE Control windows - use parent DC for speed
wndcls.style |= CS_PARENTDC | CS_DBLCLKS | CS_HREDRAW | CS_VREDRAW;
wndcls.lpszClassName = _afxWndOleControl;
if (AfxRegisterClass(&wndcls))
fRegisteredClasses |= AFX_WNDOLECONTROL_REG;
}
if (fToRegister & AFX_WNDCONTROLBAR_REG)
{
// Control bar windows
wndcls.style = 0; // control bars don't handle double click
wndcls.lpszClassName = _afxWndControlBar;
wndcls.hbrBackground = (HBRUSH)(COLOR_BTNFACE + 1);
if (AfxRegisterClass(&wndcls))
fRegisteredClasses |= AFX_WNDCONTROLBAR_REG;
}
if (fToRegister & AFX_WNDMDIFRAME_REG)
{
// MDI Frame window (also used for splitter window)
wndcls.style = CS_DBLCLKS;
wndcls.hbrBackground = NULL;
if (_AfxRegisterWithIcon(&wndcls, _afxWndMDIFrame, AFX_IDI_STD_MDIFRAME))
fRegisteredClasses |= AFX_WNDMDIFRAME_REG;
}
if (fToRegister & AFX_WNDFRAMEORVIEW_REG)
{
// SDI Frame or MDI Child windows or views - normal colors
wndcls.style = CS_DBLCLKS | CS_HREDRAW | CS_VREDRAW;
wndcls.hbrBackground = (HBRUSH) (COLOR_WINDOW + 1);
if (_AfxRegisterWithIcon(&wndcls, _afxWndFrameOrView, AFX_IDI_STD_FRAME))
fRegisteredClasses |= AFX_WNDFRAMEORVIEW_REG;
}
if (fToRegister & AFX_WNDCOMMCTLS_REG)
{
// this flag is compatible with the old InitCommonControls() API
init.dwICC = ICC_WIN95_CLASSES;
fRegisteredClasses |= _AfxInitCommonControls(&init, AFX_WIN95CTLS_MASK);
fToRegister &= ~AFX_WIN95CTLS_MASK;
}
if (fToRegister & AFX_WNDCOMMCTL_UPDOWN_REG)
{
init.dwICC = ICC_UPDOWN_CLASS;
fRegisteredClasses |= _AfxInitCommonControls(&init, AFX_WNDCOMMCTL_UPDOWN_REG);
}
if (fToRegister & AFX_WNDCOMMCTL_TREEVIEW_REG)
{
init.dwICC = ICC_TREEVIEW_CLASSES;
fRegisteredClasses |= _AfxInitCommonControls(&init, AFX_WNDCOMMCTL_TREEVIEW_REG);
}
if (fToRegister & AFX_WNDCOMMCTL_TAB_REG)
{
init.dwICC = ICC_TAB_CLASSES;
fRegisteredClasses |= _AfxInitCommonControls(&init, AFX_WNDCOMMCTL_TAB_REG);
}
if (fToRegister & AFX_WNDCOMMCTL_PROGRESS_REG)
{
init.dwICC = ICC_PROGRESS_CLASS;
fRegisteredClasses |= _AfxInitCommonControls(&init, AFX_WNDCOMMCTL_PROGRESS_REG);
}
if (fToRegister & AFX_WNDCOMMCTL_LISTVIEW_REG)
{
init.dwICC = ICC_LISTVIEW_CLASSES;
fRegisteredClasses |= _AfxInitCommonControls(&init, AFX_WNDCOMMCTL_LISTVIEW_REG);
}
if (fToRegister & AFX_WNDCOMMCTL_HOTKEY_REG)
{
init.dwICC = ICC_HOTKEY_CLASS;
fRegisteredClasses |= _AfxInitCommonControls(&init, AFX_WNDCOMMCTL_HOTKEY_REG);
}
if (fToRegister & AFX_WNDCOMMCTL_BAR_REG)
{
init.dwICC = ICC_BAR_CLASSES;
fRegisteredClasses |= _AfxInitCommonControls(&init, AFX_WNDCOMMCTL_BAR_REG);
}
if (fToRegister & AFX_WNDCOMMCTL_ANIMATE_REG)
{
init.dwICC = ICC_ANIMATE_CLASS;
fRegisteredClasses |= _AfxInitCommonControls(&init, AFX_WNDCOMMCTL_ANIMATE_REG);
}
if (fToRegister & AFX_WNDCOMMCTL_INTERNET_REG)
{
init.dwICC = ICC_INTERNET_CLASSES;
fRegisteredClasses |= _AfxInitCommonControls(&init, AFX_WNDCOMMCTL_INTERNET_REG);
}
if (fToRegister & AFX_WNDCOMMCTL_COOL_REG)
{
init.dwICC = ICC_COOL_CLASSES;
fRegisteredClasses |= _AfxInitCommonControls(&init, AFX_WNDCOMMCTL_COOL_REG);
}
if (fToRegister & AFX_WNDCOMMCTL_USEREX_REG)
{
init.dwICC = ICC_USEREX_CLASSES;
fRegisteredClasses |= _AfxInitCommonControls(&init, AFX_WNDCOMMCTL_USEREX_REG);
}
if (fToRegister & AFX_WNDCOMMCTL_DATE_REG)
{
init.dwICC = ICC_DATE_CLASSES;
fRegisteredClasses |= _AfxInitCommonControls(&init, AFX_WNDCOMMCTL_DATE_REG);
}
if (fToRegister & AFX_WNDCOMMCTL_LINK_REG)
{
init.dwICC = ICC_LINK_CLASS;
fRegisteredClasses |= _AfxInitCommonControls(&init, AFX_WNDCOMMCTL_LINK_REG);
}
if (fToRegister & AFX_WNDCOMMCTL_PAGER_REG)
{
init.dwICC = ICC_PAGESCROLLER_CLASS;
fRegisteredClasses |= _AfxInitCommonControls(&init, AFX_WNDCOMMCTL_PAGER_REG);
}
// save new state of registered controls
pModuleState->m_fRegisteredClasses |= fRegisteredClasses;
// special case for all common controls registered, turn on AFX_WNDCOMMCTLS_REG
if ((pModuleState->m_fRegisteredClasses & AFX_WIN95CTLS_MASK) == AFX_WIN95CTLS_MASK)
{
pModuleState->m_fRegisteredClasses |= AFX_WNDCOMMCTLS_REG;
fRegisteredClasses |= AFX_WNDCOMMCTLS_REG;
}
// must have registered at least as mamy classes as requested
return (fToRegister & fRegisteredClasses) == fToRegister;
}
查看 AfxRegisterClass 函数的功能：“利用这个函数在使用MFC的DLL中注册一个窗口类。如果你使用了这个函数，则当DLL卸载时，这个类会自动注销。在非DLL项目中，AfxRegisterClass标识符被定义为一个宏，映像到 Windows 函数 RegisterClass ，因为应用程序中注册的 类是自动注销的。如果你用 AfxRegisterClass 来代替RegisterClass ，那么你的代码不管是用于应用程序还是用于DLL都不用于改变。 ”
（2）查看 CFrameWnd::Create 源码：
BOOL CFrameWnd::Create(LPCTSTR lpszClassName,
LPCTSTR lpszWindowName,
DWORD dwStyle,
const RECT& rect,
CWnd* pParentWnd,
LPCTSTR lpszMenuName,
DWORD dwExStyle,
CCreateContext* pContext)
{
HMENU hMenu = NULL;
if (lpszMenuName != NULL)
{
// load in a menu that will get destroyed when window gets destroyed
HINSTANCE hInst = AfxFindResourceHandle(lpszMenuName, ATL_RT_MENU);
if ((hMenu = ::LoadMenu(hInst, lpszMenuName)) == NULL)
{
TRACE(traceAppMsg, 0, "Warning: failed to load menu for CFrameWnd.\n");
PostNcDestroy(); // perhaps delete the C++ object
return FALSE;
}
}
m_strTitle = lpszWindowName; // save title for later
if (!CreateEx(dwExStyle, lpszClassName, lpszWindowName, dwStyle,
rect.left, rect.top, rect.right - rect.left, rect.bottom - rect.top,
pParentWnd->GetSafeHwnd(), hMenu, (LPVOID)pContext))
{
TRACE(traceAppMsg, 0, "Warning: failed to create CFrameWnd.\n");
if (hMenu != NULL)
DestroyMenu(hMenu);
return FALSE;
}
return TRUE;
}
查看 CFrame::CreateEx 源码：
BOOL CWnd::CreateEx(DWORD dwExStyle, LPCTSTR lpszClassName,
LPCTSTR lpszWindowName, DWORD dwStyle,
const RECT& rect, CWnd* pParentWnd, UINT nID,
LPVOID lpParam /* = NULL */)
{
return CreateEx(dwExStyle, lpszClassName, lpszWindowName, dwStyle,
rect.left, rect.top, rect.right - rect.left, rect.bottom - rect.top,
pParentWnd->GetSafeHwnd(), (HMENU)(UINT_PTR)nID, lpParam);
}
BOOL CWnd::CreateEx(DWORD dwExStyle, LPCTSTR lpszClassName,
LPCTSTR lpszWindowName, DWORD dwStyle,
int x, int y, int nWidth, int nHeight,
HWND hWndParent, HMENU nIDorHMenu, LPVOID lpParam)
{
ASSERT(lpszClassName == NULL || AfxIsValidString(lpszClassName) ||
AfxIsValidAtom(lpszClassName));
ENSURE_ARG(lpszWindowName == NULL || AfxIsValidString(lpszWindowName));
// allow modification of several common create parameters
CREATESTRUCT cs;
cs.dwExStyle = dwExStyle;
cs.lpszClass = lpszClassName;
cs.lpszName = lpszWindowName;
cs.style = dwStyle;
cs.x = x;
cs.y = y;
cs.cx = nWidth;
cs.cy = nHeight;
cs.hwndParent = hWndParent;
cs.hMenu = nIDorHMenu;
cs.hInstance = AfxGetInstanceHandle();
cs.lpCreateParams = lpParam;
if (!PreCreateWindow(cs))
{
PostNcDestroy();
return FALSE;
}
AfxHookWindowCreate(this);
HWND hWnd = ::AfxCtxCreateWindowEx(cs.dwExStyle, cs.lpszClass,
cs.lpszName, cs.style, cs.x, cs.y, cs.cx, cs.cy,
cs.hwndParent, cs.hMenu, cs.hInstance, cs.lpCreateParams);
#ifdef _DEBUG
if (hWnd == NULL)
{
TRACE(traceAppMsg, 0, "Warning: Window creation failed: GetLastError returns 0x%8.8X\n",
GetLastError());
}
#endif
if (!AfxUnhookWindowCreate())
PostNcDestroy(); // cleanup if CreateWindowEx fails too soon
if (hWnd == NULL)
return FALSE;
ASSERT(hWnd == m_hWnd); // should have been set in send msg hook
return TRUE;
}
因为CWnd是CFrameWnd的父类所以CreateEx调用的PreCreateWindow实际是CFrameWnd::PreCreateWindow。可以说明PreCreateWindow 在窗口创建之前调用，我们可以在PreCreateWindow修改窗口属性 CREATESTRUCT cs ，修改成我们想要的窗口属性。
BOOL CMainFrame::PreCreateWindow(CREATESTRUCT& cs)
{
if( !CFrameWnd::PreCreateWindow(cs) )
return FALSE;
// TODO: 在此处通过修改
// CREATESTRUCT cs 来修改窗口类或样式
return TRUE;
}
