MFC RTTI模仿 --《深入浅出MFC》

模仿RTTI关键步骤：

1.数据结构：

struct CRuntimeClass {
    char ×strName;
    int classSize;
    static CRuntimeClass *pFirstClass;
    CRuntimeClass *pBaseClass;
    CRuntimeClass *pNextClass;
}

2.组织形式：以链表的形式组织，在不同的类中以静态成员的形式存在

#define DYNAMIC_CAST(class_name) \
public:
    static CRuntimeClass class##class_name;
    virtual CRuntimeClass *getClass() const；

struct AFX_CLASS_INIT {
 AFX_CLASS_INIT(CRuntimeClass *pnewClass);
};
AFX_CLASS_INIT::AFX_CLASS_INIT(CRuntimeClass *pnewClass) {
pnewClass->pNextClass = CRuntimeClass::pFirstClass;
CRuntimeClass::pFirstClass = pnewClass;
}
#define RUNTIMECLASS(class_name) (&class_name::class##class_name)

#define IMPLEMENT_DYNAMIC(class_name,base_class_name) \
    static char str##class_name[] = #class_name; \
    CRuntimeClass class##class_name = {str##class_name, \
    sizeof(class_name), RUNTIMECLASS(base_class_name) ,NULL)
 static AFX_CLASS_INIT init_##class_name(&class_name::class##class_name);
 CRuntimeClass *class_name::getClass() const {
 return &class_name::class##class_name;
 }

 3.举例说明：

 

class CParent :public CObject {
    DYNAMIC_CAST(CPARENT)
    ...
}

class CChild:public CParent {
    DYNAMIC_CAST(CChild)
    ...
}
IMPLEMENT_DYNAMIC(CParent, CObject)
IMPLEMENT_DYNAMIC(CChild,CParent)