YouTubeViewers/YouTubeViewers.WPF/Stores/ModalNavigationStore.cs

using System;
using YouTubeViewers.WPF.ViewModels;

namespace YouTubeViewers.WPF.Stores
{
    public class ModalNavigationStore
    {
        private ViewModelBase  _currentViewModel;

        public ViewModelBase   CurrentViewModel
        {
            get { return _currentViewModel; }
            set { 
                _currentViewModel = value;
                CurrentViewModelChanged?.Invoke();
            }
        }

        public bool IsOpen => CurrentViewModel != null;

        public event Action CurrentViewModelChanged;

        public void Close()
        {
            CurrentViewModel = null;
        }
    }
}