Xaml Attached Dependency Property

AttachedDependencyPropertySample.cpp

// Usage in Xaml
//
// <FlipView UpdateOnChange.VisualState="{Binding Path=VisualState}">
//   
//

// Header File

#pragma once

namespace FlipIt
{
    public ref class UpdateOnChange sealed
    {
    public:
        static property Windows::UI::Xaml::DependencyProperty^ VisualStateProperty
        {
            Windows::UI::Xaml::DependencyProperty^ get();
        }

        static Platform::String^ GetVisualState(Windows::UI::Xaml::DependencyObject^ obj);

        static void SetVisualState(Windows::UI::Xaml::DependencyObject^ obj, Platform::String^ value);

        static void OnVisualStateChanged(Windows::UI::Xaml::DependencyObject^ object, Windows::UI::Xaml::DependencyPropertyChangedEventArgs^ e);

    private:
        static Windows::UI::Xaml::DependencyProperty^ s_visualState;
    };
}

// Code file

#include "pch.h"
#include "UpdateOnChange.h"

using namespace FlipIt;

using namespace std;

using namespace Platform;
using namespace Windows::Foundation;
using namespace Windows::UI::Xaml;
using namespace Windows::UI::Xaml::Controls;
using namespace Windows::UI::Xaml::Interop;

DependencyProperty^ UpdateOnChange::s_visualState = DependencyProperty::RegisterAttached(
    L"VisualState",
    String::typeid,
    UpdateOnChange::typeid,
    ref new PropertyMetadata(nullptr, ref new PropertyChangedCallback(&UpdateOnChange::OnVisualStateChanged)));

DependencyProperty^ UpdateOnChange::VisualStateProperty::get()
{
    return s_visualState;
}

String^ UpdateOnChange::GetVisualState(Windows::UI::Xaml::DependencyObject^ obj)
{
    return safe_cast<String^>(obj->GetValue(s_visualState));
}

void UpdateOnChange::SetVisualState(Windows::UI::Xaml::DependencyObject^ obj, Platform::String^ value)
{
    obj->SetValue(s_visualState, value);
}

void UpdateOnChange::OnVisualStateChanged(DependencyObject^ d, DependencyPropertyChangedEventArgs^ e)
{
    String^ oldValue = safe_cast<String^>(e->OldValue);
    String^ newValue = safe_cast<String^>(e->NewValue);
    if (oldValue != newValue)
    {
        if (newValue != nullptr && newValue != "")
        {
            ContentControl^ cc = safe_cast<ContentControl^>(d);
            
            VisualStateManager::GoToState(cc, newValue, false);
        }
    }
}