inabox/InABox.Mobile/InABox.Mobile.Shared/Components/MobileView/MobileViewModel.cs

using System;
using InABox.Core;
using Xamarin.Forms;

namespace InABox.Mobile
{

    public abstract class MobileViewModel : BindableObject, IMobileViewModel
    {
        public Color SelectedColor => XF.Material.Forms.Material.Color.Surface;
        public Color SelectedTextColor => XF.Material.Forms.Material.Color.OnSurface;
        public Color UnselectedColor => XF.Material.Forms.Material.Color.Primary;
        public Color UnselectedTextColor => XF.Material.Forms.Material.Color.OnPrimary;
        
        public event MobileViewModelLoadedEvent Loaded;
        protected void OnLoaded() 
            => Loaded?.Invoke(this, new MobileViewModelLoadedEventArgs());
    }
    
    public abstract class MobileViewModel<TEntity,TShell> : MobileViewModel
        where TEntity : Entity, IRemotable, IPersistent
        where TShell : IShell<TEntity>
    {
        
        public static readonly BindableProperty ItemProperty = BindableProperty.Create(
            nameof(Item), 
            typeof(TShell), 
            typeof(MobileViewModel<TEntity,TShell>)
        );
        
        public TShell Item
        {
            get => (TShell)GetValue(ItemProperty);
            set
            {
                SetValue(ItemProperty,value);
                DoLoad();
                OnLoaded();
                OnPropertyChanged(nameof(IsChanged));
            }
        }
        
        protected abstract void DoLoad();

        public abstract bool IsChanged { get; }

        public void DoChanged() => OnPropertyChanged(nameof(IsChanged));

    }
}