Visual C ++，CArchive Serialize

Question

我使用Visual Studio 2010学习Visual C ++。 我试图使用MFC CObject的Serialize函数。 我无法使用Serialize函数加载我的对象 我的代码：

#include <afxwin.h>
#include <iostream>

using std::cout;
using std::endl;

// CMyObject

class CMyObject : public CObject
{
public:
    int x, y;
    CMyObject(int _x=0, int _y=0) : CObject(), x(_x), y(_y) {}
    void Serialize(CArchive &ar);
    void Print() const;
    DECLARE_SERIAL(CMyObject)
};

IMPLEMENT_SERIAL(CMyObject, CObject, 1)

void CMyObject::Serialize(CArchive &ar)
{
    CObject::Serialize(ar);
    if (ar.IsStoring())
        ar << x;
    else
        ar >> x;
}

void CMyObject::Print() const
{
    cout << "CMyObject (" << x << "," << y << ")" << endl;
}



int main()
{
    CMyObject cm(1,3);
    CFile fileS, fileL;
    fileS.Open(L"C:\\CMyObject.dat", CFile::modeWrite | CFile::modeCreate);
    CArchive arStore(&fileS, CArchive::store);

    cm.Print();
    cm.Serialize(arStore);
    arStore.Close();

    cm.x = 2;
    cm.Print();

    fileL.Open(L"C:\\CMyObject.dat", CFile::modeRead);
    CArchive arLoad(&fileL, CArchive::load);
    cm.Serialize(arLoad);
    cm.Print();
    arLoad.Close();
}

程序死于字符串：

    cm.Serialize(arLoad);

你能告诉我这段代码有什么问题吗？

Answer 1

您应该检查Open()的来电是否失败。完成写入后忘记关闭文件。关闭存档对象后添加fileS.Close();。

if(!fileS.Open(L"C:\\source\\CMyObject.dat", CFile::modeWrite | CFile::modeCreate))
{
    std::cout << "Unable to open output file" << std::endl;
    return 1;
}
CArchive arStore(&fileS, CArchive::store);
cm.Print();
cm.Serialize(arStore);
arStore.Close();
fileS.Close();  //  <--- close the file


if(!fileL.Open(L"C:\\source\\CMyObject.dat", CFile::modeRead))
{
    std::cout << "Unable to open input file" << std::endl;
    return 1;
}
CArchive arLoad(&fileL, CArchive::load);
cm.Serialize(arLoad);
cm.Print();
arLoad.Close();
fileL.Close();  //  <--- close the file

Answer 2

为了让MFC在反序列化期间动态创建对象，类定义必须提供不带参数的构造函数。参考：

http://msdn.microsoft.com/en-us/library/47ecfxkh.aspx