FrameworkElement.h

#pragma once
 
#include "Binding.h"
#include "ITag.h"
#include "ObservableObject.h"
#include "Variant.h"
#include <unordered_map>
 
namespace sw
{
    // 前向声明
    class DataBinding;
    class FrameworkElement;
 
    struct DataContextChangedEventArgs : EventArgs {
        DynamicObject *oldDataContext;
    };
 
    using DataContextChangedEventHandler =
        EventHandler<FrameworkElement, DataContextChangedEventArgs>;
 
    class FrameworkElement : public ObservableObject,
                             public ITag<Variant>
    {
    private:
        std::unordered_map<FieldId, std::unique_ptr<BindingBase>> _bindings{};
 
        Variant _tag = nullptr;
 
        Variant _dataContext = nullptr;
 
        DataContextChangedEventHandler _dataContextChanged;
 
    public:
        const Event<DataContextChangedEventHandler> DataContextChanged;
 
        const Property<Variant> Tag;
 
        const Property<Variant> DataContext;
 
        const ReadOnlyProperty<DynamicObject *> CurrentDataContext;
 
    protected:
        FrameworkElement();
 
        // 删除拷贝构造函数
        FrameworkElement(const FrameworkElement &) = delete;
 
        // 删除移动构造函数
        FrameworkElement(FrameworkElement &&) = delete;
 
        // 删除拷贝赋值运算符
        FrameworkElement &operator=(const FrameworkElement &) = delete;
 
        // 删除移动赋值运算符
        FrameworkElement &operator=(FrameworkElement &&) = delete;
 
    public:
        bool AddBinding(BindingBase *binding);
 
        bool AddBinding(Binding *binding);
 
        bool AddBinding(DataBinding *binding);
 
        bool RemoveBinding(FieldId propertyId);
 
        template <typename T, typename TProperty>
        bool RemoveBinding(TProperty T::*prop)
        { return RemoveBinding(Reflection::GetFieldId(prop)); }
 
    public:
        virtual Variant GetTag() const override final;
 
        virtual void SetTag(const Variant &tag) override final;
 
    protected:
        virtual void OnCurrentDataContextChanged(DynamicObject *oldDataContext);
 
    public:
        virtual FrameworkElement *GetParent() const = 0;
 
        virtual int GetChildCount() const = 0;
 
        virtual FrameworkElement &GetChildAt(int index) const = 0;
    };
}