我尝试创建控件/窗口事件,类似于在C#的Windows窗体/ WPF中完成的操作。每个事件类都包含一个参数类型,并传递它以及指向发送对象的指针。使用lambda函数时,这一切都很好,但是当我尝试向事件添加成员函数时,我得到C2276 '&': illegal operation on bound member function expression
和C2660 'Event<MouseButtonEventArgs>::add': function does not take 1 arguments
的编译错误。
如何创建一个可以从任何类中获取lambda函数和成员函数的事件类(无论该类是&#34; sender&#34;)?
Event.h
template<class Args> struct EventListener {
/* The function type to be called by the event. */
typedef function<void(ControlBaseSPtr, Args&)> ArgsFunction;
string name;
ArgsFunction function;
};
template<class Args> class Event {
/* The function type to be called by the event. */
typedef function<void(ControlBaseSPtr, Args&)> ArgsFunction;
deque<EventListener<Args>> listeners;
Event(EventDirections direction) {
this->direction = direction;
}
void add(const string& name, ArgsFunction function) {
EventListener<Args> listener = EventListener<Args>(name, function);
for (auto it = listeners.begin(); it != listeners.end(); it++) {
if (it->name == name) {
throw exception("Event::operator+= listener already exists in the event");
}
}
listeners.push_back(listener);
}
//...
};
Control.h
class ControlBase {
Event<MouseEventArgs> _eventMouseMovedGlobal;
Event<MouseButtonEventArgs> _eventMouseButtonGlobal;
ControlBase();
void onMouseMovedGlobal(ControlBaseSPtr sender, MouseEventArgs e);
};
Control.cpp
ControlBase::ControlBase() {
// Works
_eventMouseButtonGlobal.add("some name", [](ControlSPtr control, MouseButtonEventArgs e){
//...
};
// Doesn't work
_eventMouseMovedGlobal.add("some name", bind(&onMouseMovedGlobal, this, placeholders::_2))
// Doesn't work
_eventMouseMovedGlobal.add("some name", bind(&onMouseMovedGlobal, this))
}
void ControlBase::onMouseWheelGlobal(ControlBaseSPtr sender, MouseWheelEventArgs e) {
//...
}
答案 0 :(得分:0)
好吧,由于onMouseMovedGlobal
有2个输入参数,因此在创建活页夹时需要占位符或值。所以,而不是
_eventMouseMovedGlobal.add("some name", bind(&onMouseMovedGlobal, this, placeholders::_2))
你需要
_eventMouseMovedGlobal.add("some name", bind(&ControlBase::onMouseMovedGlobal, this, placeholders::_1, placeholders::_2))