为什么复制时调用析构函数？

Question

我有一个严重的问题，我使用默认的构造函数来初始化对象和一个带参数的构造函数来复制DirectX接口。

SpriteBatch spriteBatch; //Creating an Object to SpriteBatch Class 

//This Function Gets Called when Device is Created with Parameter to Device 
void LoadContent(GraphicDevice graphicDevice) 
{ 
    /*Here is the Problem, When it Assigns to the Object it creates a Temp Object and 
    Destructor gets called where I free everything, I can't use the GraphicDevice after 
    this.*/ 

    spriteBatch = SpriteBatch(graphicDevice); 
} 


//SpriteBatch Class 

class SpriteBatch 
{ 
    GraphicDevice graphicDevice; 

    public: 
    SpriteBatch(); 
    SpriteBatch(GraphicDevice graphicDevice); 
    ~SpriteBatch(); 
} 

SpriteBatch::SpriteBatch() 
{ 
} 

SpriteBatch::SpriteBatch(GraphicDevice graphicDevice) 
{ 
    this->graphicDevice = graphicDevice; 
} 

SpriteBatch::~SpriteBatch() 
{ 
    graphicDevice-Release(); 
} 

我希望在程序结束时调用析构函数，而不是在复制两个对象时调用析构函数。 我试图重载赋值运算符和复制构造函数，但没有帮助我。 有没有办法做到这一点？

Answer 1

通过引用传递，减少拷贝，临时对象的数量和他们的破坏：

void LoadContent(GraphicDevice& graphicDevice) 
{ 
    spriteBatch = SpriteBatch(graphicDevice); 
} 

然后：

SpriteBatch::SpriteBatch(GraphicDevice& graphicDevice) 
    :graphicDevice(graphicDevice) 
{ 
} 

如果你想避免新GraphicDevice为SpriteBatch每个实例，制作GraphicDevice graphicDevice;作为参考：

GraphicDevice& graphicDevice; 

这将需要在所有SpriteBatch构造函数中初始化。

Answer 2

对graphicDevice使用shared_ptr，以便仅当引用计数达到零时才会释放它。你不应该在析构函数中首先处理这个问题。