IGUIElement collection

[barakatx2]

I have an std::map that contains IGUIElements. I use this to track all my GUI elements. Lets say I add an IGUIEditBox to this map. When I try this:

controlList[id].setMultiLine(true);

This will not work because IGUIElement does not have this function. So I try to cast it as IGUIEditBox:

(gui::IGUIEditBox)controlList[id].setMultiLine(true);

And it says you can not cast with an abstract class. Can I not have edit boxes in an std collection class like this? Any ideas would be appreciated.

[TomTim]

I have an std::map that contains IGUIElements. I use this to track all my GUI elements. Lets say I add an IGUIEditBox to this map. When I try this:

controlList[id].setMultiLine(true);

This will not work because IGUIElement does not have this function. So I try to cast it as IGUIEditBox:

(gui::IGUIEditBox)controlList[id].setMultiLine(true);

And it says you can not cast with an abstract class. Can I not have edit boxes in an std collection class like this? Any ideas would be appreciated.

Save the element in a variable:

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irr::gui::IGUIEditBox*EditBox=dynamic_cast<irr::gui::IGUIEditBox*>(controlList[id]);
EditBox->setMultiLine(true);

[Acki]

(gui::IGUIEditBox)controlList[id].setMultiLine(true);

the "casting-braces" are wrong !!!
you're now casting the return value of setMultiLine(true) (which has no return value) !!!
try this:

Code: Select all

((gui::IGUIEditBox)controlList[id]).setMultiLine(true)

also are you sure to use the dot operator ???
should it not be:

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((gui::IGUIEditBox)controlList[id])->setMultiLine(true)

[TomTim]

also are you sure to use the dot operator ???
should it not be:

Code: Select all

((gui::IGUIEditBox)controlList[id])->setMultiLine(true)

This isn't right, you should cast to a pointer to a IGUIEditBox, not to a IGUIEditBox object ...

@barakatx2:

Here some advices:

1. Don't save Irrlicht objects in a container, save them as pointers to Irrlicht objects.

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#include <vector>

std::vector<IGUIElement*> GUIVector;

Otherwise you'll have to use the adress operator (&) a lot, for Irrlicht uses a lot of pointer.

2. If you wanna cast a basic type to a diverted type (hope the idiom is correct), use a dynamic_cast.

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#include <vector>
class Base{};

class Diverted:Base
{
public:
    void SomeFunctionBaseDoesNotHave(){}
};

std::vector<Base*> BaseVector;
Base*PointerToBase=new Diverted();
//PointerToBase->SomeFunctionBaseDoesNotHave(); //The object itself is diverted, but the pointer is not, so you can't call the function.
BaseList.push_back(PointerToBase); //Now how to get SomeFunctionBaseDoesNotHave?
Diverted*PointerToDiverted=dynamic_cast<Diverted*>(BaseList.at(0)); //Get first item of the vector, cast it to diverted type and save it.
PointerToDiverted->SomeFunctionBaseDoesNotHave(); //OK.

3. DON'T mix up pointers with objects. If you use a pointer without the '*', it's just an adress (__int32 or __int64, depends on your OS), no object. And an integer will not have any function at all.

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//Imagine that the used constructors exist.
IGUIEditBox Object;
IGUIEditBox*Pointer=new IGUIEditBox();
Object.getText();//OK.
Pointer->getText();//Also OK.
Object->getText();Error, Object is not able to be casted into adress.
Pointer.getText();Error, the adress is just a number, no IGUIEditBox object.

Hope you see it.

[CuteAlien]

Please do not use dynamic_cast. Irrlicht is compiled without rtti, so that won't work. Use c-casts or static_cast instead.
And your main problem is that you try to cast objects instead of casting pointers. Work with pointers instead.

[TomTim]

Please do not use dynamic_cast. Irrlicht is compiled without rtti, so that won't work.

So I understand why some of my dynamic_casts haven't worked. OK, ignore what I wrote.

[barakatx2]

(gui::IGUIEditBox)controlList[id].setMultiLine(true);

the "casting-braces" are wrong !!!
you're now casting the return value of setMultiLine(true) (which has no return value) !!!
try this:

Code: Select all

((gui::IGUIEditBox)controlList[id]).setMultiLine(true)

also are you sure to use the dot operator ???
should it not be:

Code: Select all

((gui::IGUIEditBox)controlList[id])->setMultiLine(true)

This was right. Also I am using pointers, I had just put a period incorrectly in the code I pasted for some reason @_@. But ((gui::IGUIEditbox*)controlList[id])->setMultiLine(true); works. Thank you!

[Acki]

also are you sure to use the dot operator ???
should it not be:

Code: Select all

((gui::IGUIEditBox)controlList[id])->setMultiLine(true)

This isn't right, you should cast to a pointer to a IGUIEditBox, not to a IGUIEditBox object ...

yeah, sorry, just a typo, I forgot the asterisk...

as barakatx2 already figured out it must be:

Code: Select all

((gui::IGUIEditbox*)controlList[id])->setMultiLine(true);