How to create copy constructor in C++/CX with class having properties

Question

I'm new to C++/CX. I want to create a Vector class with two properties X and Y.

In standard C++, the copy constructor is:

Vector(const Vector& v);

I translate that to C++/CX as:

Vector(const Vector^ v);

Here's the class:

Header:

ref class Vector
{
public:
    Vector();
    Vector(const Vector^ v);

    property double X;
    property double Y;
};

Implementation:

Vector::Vector()
{
    X = 0;
    Y = 0;
}

Vector::Vector(const Vector^ v)
{
    this->X = v->X;
    this->Y = v->Y;
}

But I got an error when assigning v->X to this->X as: no instance of function "Vector::X::get" matches the argument list and object (the object as type qualifiers that prevent a match).

How to implement the copy constructor correctly?

Thanks.

Answer 1

On 22/07/2012 12:05, Tyler Nguyen wrote:

I'm new to C++/CX. I want to create a Vector class with two properties X and Y.
In standard C++, the copy constructor is:

Vector(const Vector& v);

I translate that to C++/CX as:

Vector(const Vector^ v);

[...]

But I got an error when assigning v->X to this->X as: no instance of function "Vector::X::get" matches the argument list and object (the object as type qualifiers that prevent a match).

I'm not sure that it makes sense to have a copy constructor in C++/CX, since the "ref" classes are managed by reference (and the "^" is kind of like a CComPtr smart pointer).

In any case, I'd try removing the 'const' (I'm not sure there's a strong support for const-correctness in C++/CX like there is in C++):

Vector(Vector^ v)

Giovanni

Answer 2

Hi Tyler,

I'd like to move this thread to Building Metro style apps with C++ Forum for more efficient responses.

Thanks for your understanding.
Best regards,

---

Helen Zhao [MSFT]
MSDN Community Support | Feedback to us

Answer 3

Hi,

I agree with Giovanni. You should delete the const keyword. And I suggest you refer to the following codes for more information about creating a ref class with two properties:

// the header file

    ref class Factory 
    {
    private: 
	double _x; 
	double _y;
    public:
        Factory();
        Factory( Factory^ f);
	property double X
	{
		double get(){return _x; }
		void set(double x)
		{
			if(x!=_x)
			{
				_x=x;
			}
		}
	}
	property double Y
	{
		double get(){	return _y;}
		void set(double y)
		{
			if(_y!=y)
			{
			       _y=y;
			}
		}
	}
    };

//the cpp file
Factory::Factory()
{
	_x=0;
	_y=0;
}

Factory::Factory( Factory^ f)
{
	this->X=f->X;
	this->Y=f->Y;
}

I hope this reply is helpful to you. If you have any questions, please feel free to let me know.
Best regards,

---

Helen Zhao [MSFT]
MSDN Community Support | Feedback to us