extend class and casting

[Andreoli Carlo]

Basically i have 2 class (extended_1_GrObject and extended_2_GrObject) that derive from a general abstract class(basicGrObject):

public ref class basicGrObject abstract
{
public:
	basicGrObject(){}
	/*
	* Derived class must implement this function
	*/
	virtual void calculate() abstract;
protected:
	~basicGrObject(){}
};

public ref class extended_1_GrObject : public basicGrObject
{
public:
	extended_1_GrObject()
	{
		// my code 
	}
	virtual void calculate() override
	{
		// my code 
	}
protected:
	~extended_1_GrObject()
	{
		// my code 
	}
};
public ref class extended_2_GrObject : public basicGrObject
{
public:
	extended_2_GrObject()
	{
		// my code 
	}
	virtual void calculate() override
	{
		// my code 
	}
protected:
	~extended_2_GrObject()
	{
		// my code 
	}
};

In my code i create a list of this object and foreach element i have to call the calculate method

System::Collections::ArrayList ^my_list=gcnew System::Collections::ArrayList();

extended_1_GrObject ^extended_cl_1=gcnew extended_1_GrObject();
my_list->Add(extended_cl_1);
extended_2_GrObject ^extended_cl_2=gcnew extended_2_GrObject();
my_list->Add(extended_cl_2);
//doing this many time

//other sample code
for (int i=0;i<my_list->Count;i++) {
	
	//by now my bad bad way of calling the same method is
	if (my_list[i]->GetType()->Name=="extended_1_GrObject" ) {
		extended_1_GrObject ^tmp=static_cast<extended_1_GrObject^>(my_list[i]);
		tmp->calculate();
	}
	else if (my_list[i]->GetType()->Name=="extended_2_GrObject" ) {
		extended_2_GrObject ^tmp=static_cast<extended_2_GrObject^>(my_list[i]);
		tmp->calculate();
	}
}

i really don't like to do the ' my_list[i]->GetType()->Name=="extended_1_GrObject" ' is there some way to avoid that problem, my real class have list of 10000 elements and 10000 string comparison are very very heavy

modified on Thursday, March 18, 2010 7:29 AM

[teejayem]

This should work for you (note: psuedo code).

extended_1_GrObject ^extended_cl_1=gcnew extended_1_GrObject();
my_list->Add(extended_cl_1);
extended_2_GrObject ^extended_cl_2=gcnew extended_2_GrObject();
my_list->Add(extended_cl_2);

//other sample code
for (int i=0;i<my_list->Count;i++) {

//by now my bad bad way of calling the same method is
//if (my\_list\[i\]->GetType()->Name=="extended\_1\_GrObject" ) {
//	extended\_1\_GrObject ^tmp=static\_cast<extended\_1\_GrObject^>(my\_list\[i\]);
//	tmp->calculate();
//}
//else if (my\_list\[i\]->GetType()->Name=="extended\_2\_GrObject" ) {
//	extended\_2\_GrObject ^tmp=static\_cast<extended\_2\_GrObject^>(my\_list\[i\]);
//	tmp->calculate();
//}

    basicGrObject ^tmp = static\_cast<basicGrObject^>(my\_list\[i\]);
    tmp->calculate();

}

Don't be overcome by evil, but overcome evil with good

[Andreoli Carlo]

Sometimes looking for something simple is the best way...thank you :thumbsup: