i'm having trouble with syntax regarding c++ Windows Forms..
this is how you obviously do it in a regular cpp project: http://www.cplusplus.com/doc/tutorial/structures/
but its not the same in windows forms :/
any help??
THANKS!
btw, i figured it out!
you must create a new class in the project...
call it, Player.h
in the new class, you must instantiate the class like below
to make it a managed class so it fits well with the managed code
in the forms (notice ref class keyword)
struct markedPos
{
int xPos;
int yPos;
};
ref class Player
{
public:
Player()
{
}
protected:
private:
};
then simply in the forms.h file, you must include the new class like any other class:
#include "Player.h"
and all you have to do is make an instance of the player in your forms and it'll work like magic! What i've learned: Do all your heavy lifting in the managed classes outside of the forms... which work just like your regular c++ classes...
cheers!
** You don't need to use managed code! if your getting problems with it, just remove 'ref' before class name
Related
Quick note: I have checked other topics and could not identify the correct syntax.
class Pet : public QObject
{
Q_OBJECT
Q_ENUMS(PetStatus)
public:
enum PetStatus { Stun, Rooted };
...
}
qmlRegisterType<Pet>(); //In other class.
This class is used in a QList within PetTeam which is used in a QList within PetStage. The two higher classes do not have enums. The PetStage object alone is sent to the QML and from there everything else is accessed from within QML as it is aware of the hierarchy.
petStage.team[1].pet[2].name //Works in QML
The problem I'm having is I want to use the enum in QML and I am unaware of the correct syntax to use in QML so that
console.log(X.Rooted) //prints 1; I thought Pet.Rooted would work but it does not
functions correctly.
Solution is to to create another qmlRegisterType
qmlRegisterType<Pet>("PetStatus", 1, 0, "PetStatus");
from there you would import into the QMLscript
import PetStatus 1.0
and call it from QML using
PetStatus.Rooted //Or whatever naming convention you used for your elements
I am trying to replace Poco::AutoPtr with some alternative in boost. Here is what I have discovered so far:
What I have: below classess are being used with Poco::AutoPtr. They need to implement reference counted method with implementing duplicate() and release() methods.
I am using above referece_counted.h and Poco::AutoPtr in a complex class hierarchy with multiple inheritance and c++ diamond problems.
A simplified version of classes would look something like this
class A : virtual public ReferenceCounted
{
...
}
class B : public A
{
...
}
class C : public A
{
...
}
class D : public A, B
{
...
}
and the list goes on for few more level deep. I know that this needs to be refactored with a simplified hierarchy but I wanna remove Poco::AutoPtr first with proper replacement in boost:
What I have found so far:
I have found that boost::intrusive_ptr is the closest smart pointer that can be a good replacement of Poco::AutoPtr.
I am however not able to implement the proper solution with this because the intrusive_ptr requires intrusive_ptr_add_ref and intrusive_ptr_release methods created specifically for each class with which I need to use the pointer. I tried using templates but still not having proper solution at hand.
Also one more issue is that I need to typecast from base to derived class many times.
is intrusive_ptr is the correct smart pointer for this usage ? and if yes.. can anybody give me suggestion regarding how to use the same ?
I am however not able to implement the proper solution with this
because the intrusive_ptr requires intrusive_ptr_add_ref and
intrusive_ptr_release methods created specifically for each class with
which I need to use the pointer.
No-no. It is should not be hard. As Boost documentation says:
On compilers that support argument-dependent lookup,
intrusive_ptr_add_ref and intrusive_ptr_release should be defined in
the namespace that corresponds to their parameter; otherwise, the
definitions need to go in namespace boost.
Try this: main.cpp (built ok with "g++ main.cpp -o main -lboost_system")
#include <boost/intrusive_ptr.hpp>
class MyObject
{
public:
void duplicate(){
// ...
}
void release(){
// ...
}
};
namespace boost {
template <class T>
void intrusive_ptr_add_ref( T * po ) {
po->duplicate(); // your internal realization
}
template <class T>
void intrusive_ptr_release( T * po ) {
po->release();
}
}
int main(int argc, char **argv)
{
// ...
boost::intrusive_ptr<MyObject> ptr( new MyObject );
boost::intrusive_ptr<MyObject> ptr2 = ptr; // should work
}
I am writing an GL effect system in my application so i have a superclass called
cEffect - which handles loading/parsing configuration file for each effect
and other inherited classess
cFX<name> - for every effect i add ( blur, bloom, chaos,... ).
The code is simplified here but looks like this:
Class cEffect
{
public:
bool ParseString(...);
private:
int m_nStartFrame;
int m_nEndFrame;
float m_fSpeed;
};
// Blur effect
Class cFXBlur : public cEffect
{
public:
bool RenderFrame(...);
};
// Bloom effect
Class cFXBloom : public cEffect
{
public:
bool RenderFrame(...);
};
// Scene drawing effect
Class cFXScene : public cEffect
{
public:
bool RenderFrame(...);
};
// Clear the depth/color buffer
Class cFXClearBuffers : public cEffect
{
public
bool RenderFrame(...);
}
Now, the demo engine handles a
std::vector<cEffect *> m_pvEffects;
Vector that has a list of effects added.
And when an effect is added to the current time (let's say i add a blur)
i add it like:
// Blur to be added
cEffect *newEffect = new cFXBlur;
newEffect->SetStartTime(x);
newEffect->SetEndTime(y);
newEffect->SetPower(13.0f);
newEffect->SetTexture(...);
// Now add the effect to the effects list.
m_pvEffects.push_back(newEffect);
Now, when i render i iterate through m_pvEffects list - but also i would like to call
an RenderFrame method ( which is public in every CFX<name> effect).
(*it)->RenderFrame(...)
But compiler says:
error C2039: 'RenderFrame' : is not a member of 'CEffect'
I kinda understand why it happens but can't really think of a way how can i fix this,
can you guys help me out please - it seems like i lost the plot ...
Thanks for any suggestion, what can i do to add CFX to a cEffect vector and later
use -> RenderFrame method?
You should change your class cEffect to:
Class cEffect
{
public:
bool ParseString(...);
virtual bool RenderFrame(...) = 0;
private:
int m_nStartFrame;
int m_nEndFrame;
float m_fSpeed;
};
You need the keyword virtual, if you want to redefine a method in a subclass. The = 0 makes the class cEffect abstract (i.e. you cannot create an object directly of the type cEffect), therefore subclasses must implement the method RenderFrame(...)
The error occurs, because cEffect has no member function called RenderFrame. What you want is a virtual function, a fundamental concept of object oriented programming. Basically you need to add a function
virtual bool RenderFrame(...);
to your cEffect definition. The virtual keyword basically tells the compiler to resolve it at runtime. This means if you call this method on a cEffect pointer or a reference, the corresponding method of the concrete derived class this pointer or reference point to is called. In this case you should also declare the method as virtual in all derived classes (although this is not neccessary, it makes your code clearer).
If you do not want the base class method to do anything and you want to require all derived classes to override it with their own implementation, then you can make this method pure virtual in the base class, by decralring it like
virtual bool RenderFrame(...) = 0;
This basically tells the compiler, that this is an abstract method, which doesn't have a concrete implementation and is only implemented by derived classes.
This is a very simplified explanation (appologies to every expert who thinks my wordings not 100% exact). You should read some more material on object oriented programming, especially in conjunction with C++.
I'm trying to figure out how to wrap a boost::function member (used as an event callback) of an unmanaged class with a C++/CLI class event. I do not have control over the unmanaged class. All I can do is figure out how to write the C++/CLI class properly.
Here's the example unmanaged class:
class X
{
public:
boost::function<void (double)> XChanged;;
void Set(double x)
{
XChanged(x)
}
};
I've tried many things, but I keep running into problems. I'm sure it's easier than it appears to be. Any help would be greatly appreciated!
CLI probably won't let you declare a boost::function as a static member. Make it a pointer:
boost::function<void(double> *XChanged;
Then allocate/deallocate in the constructor and finalizer and call it with (*XChanged)(arg);
If I use /clr:oldSyntax the following should work:
public __value enum IceCreamFlavors
{
Vanilla,
Chocolate,
Sardine,
};
what is the equivalent in non-oldSyntax? How do I declare a "managed" enum in Managed C++ for .NET 2.0?
Edit:
when I follow JaredPar's advice, then if I try to pass an IceCreamFlavor to a function with the signature:
OrderFlavor(IceCreamFlavors flav)
by running
OrderFlavor(IceCreamFlavors::Sardine)
I get the error:
'IceCreamFlavors Sardine' : member function redeclaration not allowed
Try
enum class IceCreamFlavors {
Vanilla,
Chocolate,
Sardine,
};
Are you, by any chance, trying to declare your enum inside another class?
ie:
public ref class Icecream
{
public enum class flavours
{
Mint,
Vanilla,
Guac
};
};
If you are, I would guess that you need to move it out so that it is its own class instead of a nested one. (Does managed c++ allow nested classes?) My impression is that you used to be able to do it unmanaged style inside another class, but since its its own class now, you probably shouldn't be nesting them. I might be wrong. My knowledge of managed c++ and c# is kind of weak.