INotifyCollectionChanged.h

#pragma once
 
#include "Event.h"
#include "IList.h"
 
namespace sw
{
    // 前向声明
    class INotifyCollectionChanged;
    class NotifyCollectionChangedEventArgs;
 
    using NotifyCollectionChangedEventHandler =
        EventHandler<INotifyCollectionChanged, NotifyCollectionChangedEventArgs>;
 
    enum class NotifyCollectionChangedAction {
        Add,     
        Remove,  
        Replace, 
        Move,    
        Reset    
    };
 
    class NotifyCollectionChangedEventArgs : public EventArgs
    {
    public:
        NotifyCollectionChangedAction action =
            NotifyCollectionChangedAction::Reset;
 
        IList *list = nullptr;
 
        int index = -1;
 
        int oldIndex = -1;
    };
 
    class INotifyCollectionChanged
    {
    public:
        Event<NotifyCollectionChangedEventHandler> CollectionChanged{
            Event<NotifyCollectionChangedEventHandler>::Init(this)
                .Delegate([](INotifyCollectionChanged *self) -> NotifyCollectionChangedEventHandler & {
                    return self->GetCollectionChangedEventDelegate();
                }) //
        };
 
        virtual ~INotifyCollectionChanged() = default;
 
    protected:
        virtual NotifyCollectionChangedEventHandler &GetCollectionChangedEventDelegate() = 0;
    };
}