Question

How to Define or Implement C# Property in ISO C++ ?

Assume following C# code :

int _id;

int ID
{
    get { return _id; }
    set { _id = value; }
}

I know C# convert the get and set lines to getXXX and setXXX methods in compile time. in C++ , programmers usually define these two function manually like :

int _id;

int getID() { return _id; }
void setID(int newID) { _id = newID; }

but, I want to have the C# syntax or a stuff like it in order to have a simple usability.
In C#, we can use properties like :

ID = 10;              // calling set function
int CurrentID = ID;   // calling get function

In C++, we can use our function like :

setID(10);                 // calling set function
int CurrentID = getID();   // calling get function

Now tell me how can I implement the C# properties in ISO C++.

thanks.

Answer 1

As Alexandre C. has already stated, it’s very awkward and not really worth it, but to give an example of how you might do it.

template <typename TClass, typename TProperty>
class Property
{
    private:
        void (TClass::*m_fp_set)(TProperty value);
        TProperty (TClass::*m_fp_get)();
        TClass * m_class;

        inline TProperty Get(void)
        {
            return (m_class->*m_fp_get)();
        }

        inline void Set(TProperty value)
        {
            (m_class->*m_fp_set)(value);
        }

    public:
        Property()
        {
            m_class = NULL;
            m_fp_set = NULL;
            m_fp_set = NULL;
        }

        void Init(TClass* p_class, TProperty (TClass::*p_fp_get)(void), void (TClass::*p_fp_set)(TProperty))
        {
            m_class = p_class;
            m_fp_set = p_fp_set;
            m_fp_get = p_fp_get;
        }

        inline operator TProperty(void)
        {
            return this->Get();
        }

        inline TProperty operator=(TProperty value)
        {
            this->Set(value);
        }
};

In your class where you wish to use it, you create a new field for the property, and you must call Init to pass your get/set methods to the property. (pref in .ctor).

class MyClass {
private:
    int _id;

    int getID() { return _id; }
    void setID(int newID) { _id = newID; }
public:
    Property<MyClass, int> Id;

    MyClass() {
        Id.Init(this, &MyClass::getID, &MyClass::setID);
    }
};