事件聚合器（Event Aggregator）允许不同的组件订阅和发布事件，而不需要知道事件的发布者和订阅者是谁，模块可在不直接相互引用的情况下通信，实现模块间的松耦合。事件聚合器常用于C#语言中，以下为C++语言的简单实现。

C++事件聚合器的实现

#pragma once
#include <map>
#include <functional>
#include <vector>
#include <iostream>class EventBase
{
};template<typename TEventArg>
class PubSubEvent : public EventBase
{
public:void Sub(std::function<void(TEventArg*)> action){actions.push_back(action);}void Pub(TEventArg* arg){for (auto action : actions){action(arg);}}private:std::vector<std::function<void(TEventArg*)>> actions;
};class EventAggregator
{
public:template<typename T>static T* GetEvent(){auto name = typeid(T).raw_name();auto itor = events.find(name);if (itor != events.end()){return static_cast<T*>(itor->second);}else{events[name] = new T();return static_cast<T*>(events[name]);}}private:static std::map<const char*, EventBase*> events;
};std::map<const char*, EventBase*> EventAggregator::events;

Demo

#include <iostream>
#include "EventAggregator.h"class TestEventArg
{
public:TestEventArg(std::string name){this->name = name;}public:std::string name;
};class TestEvent : public PubSubEvent<TestEventArg>
{};class TestClass
{
public:void DoEvent(TestEventArg* arg){std::cout << "TestClass : " << arg->name << std::endl;}
};void test(TestEventArg* arg)
{std::cout << arg->name << std::endl;
}int main()
{TestClass testClass;EventAggregator::GetEvent<TestEvent>()->Sub(test);EventAggregator::GetEvent<TestEvent>()->Sub(std::bind(&TestClass::DoEvent, &testClass, std::placeholders::_1));EventAggregator::GetEvent<TestEvent>()->Pub(new TestEventArg("hello"));EventAggregator::GetEvent<TestEvent>()->Pub(new TestEventArg("world"));
}