MFC 运行时信息(RTTI)
思路
运行时的信息是属于类的,将CRuntimeClass的类当做类的静态成员变量,再用指针连接整个类的继承体系,就可以得到类的运行时信息。由于代码的相似度很高,用宏定义的方法可以更方便。
CRuntimeClass定义
struct CRuntimeClass
{
// Attributes
LPCSTR m_lpszClassName;
int m_nObjectSize;
UINT m_wSchema; // schema number of the loaded class
CObject* (PASCAL* m_pfnCreateObject)(); // NULL => abstract class
CRuntimeClass* m_pBaseClass;
// CRuntimeClass objects linked together in simple list
static CRuntimeClass* pFirstClass; // start of class list
CRuntimeClass* m_pNextClass; // linked list of registered classes
};
相关宏定义和类
struct AFX_CLASSINIT
{
AFX_CLASSINIT(CRuntimeClass* pNewClass);
};
#define RUNTIME_CLASS(class_name) \
(&class_name::class##class_name)
#define DECLARE_DYNAMIC(class_name) \
public: \
static CRuntimeClass class##class_name; \
virtual CRuntimeClass* GetRuntimeClass() const;
#define _IMPLEMENT_RUNTIMECLASS(class_name, base_class_name, wSchema, pfnNew) \
static char _lpsz##class_name[] = #class_name; \
CRuntimeClass class_name::class##class_name = { \
_lpsz##class_name, sizeof(class_name), wSchema, pfnNew, \
RUNTIME_CLASS(base_class_name), NULL }; \
static AFX_CLASSINIT _init_##class_name(&class_name::class##class_name); \
CRuntimeClass* class_name::GetRuntimeClass() const \
{ return &class_name::class##class_name; } \
#define IMPLEMENT_DYNAMIC(class_name, base_class_name) \
_IMPLEMENT_RUNTIMECLASS(class_name, base_class_name, 0xFFFF, NULL)
mfc.h
#define BOOL int
#define TRUE 1
#define FALSE 0
#define LPCSTR LPSTR
typedef char* LPSTR;
#define UINT int
#define PASCAL _stdcall
#define NULL 0
//#include <iostream>
class CObject;
struct CRuntimeClass
{
// Attributes
LPCSTR m_lpszClassName;
int m_nObjectSize;
UINT m_wSchema; // schema number of the loaded class
CObject* (PASCAL* m_pfnCreateObject)(); // NULL => abstract class
CRuntimeClass* m_pBaseClass;
// CRuntimeClass objects linked together in simple list
static CRuntimeClass* pFirstClass; // start of class list
CRuntimeClass* m_pNextClass; // linked list of registered classes
};
struct AFX_CLASSINIT
{
AFX_CLASSINIT(CRuntimeClass* pNewClass);
};
#define RUNTIME_CLASS(class_name) \
(&class_name::class##class_name)
#define DECLARE_DYNAMIC(class_name) \
public: \
static CRuntimeClass class##class_name; \
virtual CRuntimeClass* GetRuntimeClass() const;
#define _IMPLEMENT_RUNTIMECLASS(class_name, base_class_name, wSchema, pfnNew) \
static char _lpsz##class_name[] = #class_name; \
CRuntimeClass class_name::class##class_name = { \
_lpsz##class_name, sizeof(class_name), wSchema, pfnNew, \
RUNTIME_CLASS(base_class_name), NULL }; \
static AFX_CLASSINIT _init_##class_name(&class_name::class##class_name); \
CRuntimeClass* class_name::GetRuntimeClass() const \
{ return &class_name::class##class_name; } \
#define IMPLEMENT_DYNAMIC(class_name, base_class_name) \
_IMPLEMENT_RUNTIMECLASS(class_name, base_class_name, 0xFFFF, NULL)
class CObject
{
public:
CObject::CObject() {
}
CObject::~CObject() {
}
virtual CRuntimeClass* GetRuntimeClass() const;
BOOL IsKindOf(const CRuntimeClass* pClass) const;
public:
static CRuntimeClass classCObject;
};
class CCmdTarget : public CObject
{
DECLARE_DYNAMIC(CCmdTarget)
public:
CCmdTarget::CCmdTarget() {
}
CCmdTarget::~CCmdTarget() {
}
};
class CWinThread : public CCmdTarget
{
DECLARE_DYNAMIC(CWinThread)
public:
CWinThread::CWinThread() {
}
CWinThread::~CWinThread() {
}
virtual BOOL InitInstance() {
return TRUE;
}
virtual int Run() {
return 1;
}
};
class CWnd;
class CWinApp : public CWinThread
{
DECLARE_DYNAMIC(CWinApp)
public:
CWinApp* m_pCurrentWinApp;
CWnd* m_pMainWnd;
public:
CWinApp::CWinApp() {
//this->
m_pCurrentWinApp = this;
}
CWinApp::~CWinApp() {
}
virtual BOOL InitApplication() {
return TRUE;
}
virtual BOOL InitInstance() {
return TRUE;
}
virtual int Run() {
return CWinThread::Run();
}
};
class CDocument : public CCmdTarget
{
DECLARE_DYNAMIC(CDocument)
public:
CDocument::CDocument() {
}
CDocument::~CDocument() {
}
};
class CWnd : public CCmdTarget
{
DECLARE_DYNAMIC(CWnd)
public:
CWnd::CWnd() {
}
CWnd::~CWnd() {
}
virtual BOOL Create();
BOOL CreateEx();
virtual BOOL PreCreateWindow();
};
class CFrameWnd : public CWnd
{
DECLARE_DYNAMIC(CFrameWnd)
public:
CFrameWnd::CFrameWnd() {
}
CFrameWnd::~CFrameWnd() {
}
BOOL Create();
virtual BOOL PreCreateWindow();
};
class CView : public CWnd
{
DECLARE_DYNAMIC(CView)
public:
CView::CView() {
}
CView::~CView() {
}
};
// global function
CWinApp* AfxGetApp();
mfc.cpp
#include "my.h" // it should be mfc.h, but for CMyWinApp definition, so...
extern CMyWinApp theApp;
CRuntimeClass* CRuntimeClass::pFirstClass = NULL;
AFX_CLASSINIT::AFX_CLASSINIT(CRuntimeClass* pNewClass)
{
pNewClass->m_pNextClass = CRuntimeClass::pFirstClass;
CRuntimeClass::pFirstClass = pNewClass;
}
static char szCObject[] = "CObject";
CRuntimeClass CObject::classCObject ={ szCObject, sizeof(CObject), 0xffff, NULL, NULL, NULL };
static AFX_CLASSINIT _init_CObject(&CObject::classCObject);
CRuntimeClass* CObject::GetRuntimeClass() const
{
return &CObject::classCObject;
}
BOOL CObject::IsKindOf(const CRuntimeClass* pClass) const{
CRuntimeClass* pClassThis = GetRuntimeClass();
while (pClassThis != NULL){
if (pClassThis == pClass){
return TRUE;
}
pClassThis = pClassThis->m_pBaseClass;
}
return FALSE;
}
BOOL CWnd::Create()
{
return TRUE;
}
BOOL CWnd::CreateEx()
{
PreCreateWindow();
return TRUE;
}
BOOL CWnd::PreCreateWindow()
{
return TRUE;
}
BOOL CFrameWnd::Create()
{
CreateEx();
return TRUE;
}
BOOL CFrameWnd::PreCreateWindow()
{
return TRUE;
}
IMPLEMENT_DYNAMIC(CCmdTarget, CObject)
IMPLEMENT_DYNAMIC(CWinThread, CCmdTarget)
IMPLEMENT_DYNAMIC(CWinApp, CWinThread)
IMPLEMENT_DYNAMIC(CWnd, CCmdTarget)
IMPLEMENT_DYNAMIC(CFrameWnd, CWnd)
IMPLEMENT_DYNAMIC(CDocument, CCmdTarget)
IMPLEMENT_DYNAMIC(CView, CWnd)
// global function
CWinApp* AfxGetApp()
{
return theApp.m_pCurrentWinApp;
}
my.h
//#include <iostream>
#include "mfc.h"
class CMyWinApp : public CWinApp
{
DECLARE_DYNAMIC(CMyWinApp)
public:
CMyWinApp::CMyWinApp() {
}
CMyWinApp::~CMyWinApp() {
}
virtual BOOL InitInstance();
};
class CMyFrameWnd : public CFrameWnd
{
public:
CMyFrameWnd();
~CMyFrameWnd() {
}
};
class CMyDoc : public CDocument
{
public:
CMyDoc::CMyDoc() {
}
CMyDoc::~CMyDoc() {
}
};
class CMyView : public CView
{
public:
CMyView::CMyView() {
}
CMyView::~CMyView() {
}
};
// global function
void PrintAllClasses();
my.cpp
#include "my.h"
#include <iostream>
#include <iomanip>
using namespace std;
IMPLEMENT_DYNAMIC(CMyWinApp, CWinApp)
CMyWinApp theApp;
BOOL CMyWinApp::InitInstance()
{
m_pMainWnd = new CMyFrameWnd;
return TRUE;
}
CMyFrameWnd::CMyFrameWnd()
{
Create();
}
void PrintAllClasses()
{
CRuntimeClass* pClass = NULL;
cout << "_______________________________________CRuntimeClass's infromation__________________________________________\n\n";
cout << setw(10) << "m_lpszClassName\t\tm_nObjectSize\tm_wSchema\tm_pfnCreateObject\tm_pBaseClass\tm_pNextClass\n";
// just walk through the simple list of registered classes
for (pClass = CRuntimeClass::pFirstClass; pClass != NULL;
pClass = pClass->m_pNextClass)
{
cout << setw(15) << pClass->m_lpszClassName << "\t";
cout << setw(15) << pClass->m_nObjectSize << "\t";
cout << setw(15) << pClass->m_wSchema << "\t";
cout << setw(20) << pClass->m_pfnCreateObject << "\t";
cout << setw(20) << pClass->m_pBaseClass << "\t";
cout << setw(10) << pClass->m_pNextClass << "\t";
cout << setw(10) << " address " << pClass << "\n";
}
cout << "链表头指针为 " << CRuntimeClass::pFirstClass << endl;
}
//------------------------------------------------------------------
// main
//------------------------------------------------------------------
void main()
{
CWinApp* pApp = AfxGetApp();
pApp->InitApplication();
pApp->InitInstance();
pApp->Run();
PrintAllClasses();
cout << "______________RTTI______________" << "\n";
cout << pApp->IsKindOf(RUNTIME_CLASS(CMyWinApp)) << endl;
cout << pApp->IsKindOf(RUNTIME_CLASS(CWinApp)) << endl;
cout << pApp->IsKindOf(RUNTIME_CLASS(CWinThread)) << endl;
cout << pApp->IsKindOf(RUNTIME_CLASS(CCmdTarget)) << endl;
cout << pApp->IsKindOf(RUNTIME_CLASS(CObject)) << endl;
cout << pApp->IsKindOf(RUNTIME_CLASS(CWnd)) << endl;
}
//------------------------------------------------------------------
结果