我正在尝试创建类似于在 C# 的 Windows 窗体/WPF 中完成的控件/窗口事件。每个事件类都包含一个参数类型并传递它以及一个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,我收到了C2276 '&': illegal operation on bound member function expression
and的编译错误C2660 'Event<MouseButtonEventArgs>::add': function does not take 1 arguments
。
我将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(无论该类是否是“发送者”)?
事件.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);
}
//...
};
控制.h
class ControlBase {
Event<MouseEventArgs> _eventMouseMovedGlobal;
Event<MouseButtonEventArgs> _eventMouseButtonGlobal;
ControlBase();
void onMouseMovedGlobal(ControlBaseSPtr sender, MouseEventArgs e);
};
控制文件
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) {
//...
}
好吧,由于onMouseMovedGlobal
有 2 个输入参数,因此在创建活页夹时,您需要为它们都设置占位符或值。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))
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