| Diagnostics | |
| virtual void AssertValid( ) const; | Validates this object's integrity. |
| virtual void Dump( CDumpContext& dc ) const; | Produces a diagnostic dump of this object. |
| Serialization | |
| BOOL IsSerializable( ) const; | Tests to see whether this object can be serialized. |
| virtual void Serialize( CArchive& ar ); | Loads or stores an object from/to an archive. |
| Miscellaneous | |
| virtual CRuntimeClass* GetRuntimeClass( ) const; | Returns the CRuntimeClass structure corresponding to this object's class. |
| BOOL IsKindOf( const CRuntimeClass* pClass ) const; | Tests this object's relationship to a given class. |
| You can choose from four levels of functionality when deriving a class from CObject:
1: Diagnostic memory management
No macro just derive from CObject.
Override void AssertValid() and void Dump(CDumpContext& dc);
We can use Diagnostic Dumping With the help of afxDump object.
Example : afxDump << myObject.
Note: Automatic Dump of Undeleted Objects is done by the framework. There is no relation with
CObject::Dump. 2: Support for run-time class information
DECLARE_DYNAMIC(class_name) in Header file and IMPLEMENT_DYNAMIC(class_name,
base_class_name) included in the class implementation(.cpp).
You can then use the RUNTIME_CLASS macro and the CObject::IsKindOf function to determine the class of
your objects at run time.
3: Support for run-time class information and dynamic creation
DECLARE_DYNCREATE(class_name) IMPLEMENT_DYNCREATE(class_name, base_class_name)
Object can be created dynamically using
CObject* CreateObject();
static CObject* PASCAL CreateObject( LPCSTR lpszClassName );
static CObject* PASCAL CreateObject( LPCWSTR lpszClassName);
Support for run-time class information, dynamic creation, and serialization
DECLARE_SERIAL(class_name) IMPLEMENT_SERIAL (class_name, base_class_name, wSchema)
Note: Above macros are applicable to only CObject’s derived class.
If you implement case 2 there is no need to implement case 1.(compiler error)
If you implement case 3 there is no need to implement case 1 and case 2. |
| Sample source code. |
| #pragma once
// CMyObject command target
class CMyObject : public CObject
{
DECLARE_SERIAL(CMyObject)
public:
CMyObject();
virtual ~CMyObject();
virtual void Serialize(CArchive& ar);
//get and Set
inline __int64& PhoneNumber()
{
return m_nPhoneNumber;
}
//only Get
inline CString& Name()
{
return m_strName;
}
#ifdef _DEBUG
virtual void AssertValid() const;
#ifndef _WIN32_WCE
virtual void Dump(CDumpContext& dc) const;
#endif
#endif
//Private member variables.
__int64 m_nPhoneNumber;
CString m_strName;
}; |
| // MyObject.cpp : implementation file
#include "stdafx.h"
#include "MyObject.h"
#define new DEBUG_NEW //Assists in finding memory leaks.
// CMyObject
IMPLEMENT_SERIAL( CMyObject, CObject, VERSIONABLE_SCHEMA | 1 )
CMyObject::CMyObject()
{
m_nPhoneNumber = -1;
m_strName = _T("Sen SD");
}
CMyObject::~CMyObject()
{
} // CMyObject member functions
void CMyObject::Serialize(CArchive& ar)
{
if (ar.IsLoading())
{
////it is not working I don't know.
// will not work for direct call of Serialize.
UINT nVersion = ar.GetObjectSchema();
switch(nVersion)
{
case -1:
//version Unknown.
ar >> m_nPhoneNumber;//call Current version's deserialize code.
ar >> m_strName;
break;
case 0:
// read in previous version of this object
break;
case 1:
//Current version.
ar >> m_nPhoneNumber;
ar >> m_strName;
break;
default:
// report unknown version of
// this object
break;
}
}
else
{
ar << m_nPhoneNumber;
ar << m_strName;
}
}
#ifdef _DEBUG
void CMyObject::AssertValid() const
{
__super::AssertValid();
}
#ifndef _WIN32_WCE
void CMyObject::Dump(CDumpContext& dc) const
{
__super::Dump(dc);// Displays the class name.
dc << "Phone Number : " << m_nPhoneNumber << "\n";
dc << "Name : " << m_strName << "\n";
}
#endif
#endif //_DEBUG |
| Sample code How to use CMyObject class. |
| void CTestMfcDlg::TestStart()
{
CMyObject* pMyObject = (CMyObject*) CRuntimeClass::CreateObject(_T("CMyObject"));
BOOL isKind = pMyObject->IsKindOf(RUNTIME_CLASS( CMyObject));
pMyObject->PhoneNumber() = 9846000000; #ifdef _DEBUG
afxDump << pMyObject;
#endif //_DEBUG
::WriteObject( _T("C:\\CMyObject.arc"), pMyObject);
delete pMyObject; CMyObject* pReadMyObject = ::ReadObject( _T("C:\\CMyObject.arc"));
afxDump << pReadMyObject;
#ifdef _DEBUG
delete pReadMyObject;
#endif //_DEBUG
} |
| CMyObject* ReadObject( const CString& strFilePath)
{
CFile readingFile( strFilePath,CFile::modeRead);
CArchive readingArchive(&readingFile,CArchive::load);
CMyObject *pFileObject = new CMyObject();
pFileObject->Serialize( readingArchive);
readingFile.Close();
readingArchive.Close();
return pFileObject;
}
void WriteObject( const CString& strFilePath, CMyObject *pObj)
{
CFile storingFile( strFilePath,CFile::modeCreate | CFile::modeWrite);
CArchive storingArchive(&storingFile,CArchive::store);
pObj->Serialize( storingArchive);
storingArchive.Close();
storingFile.Close();
} |
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