MvxBindableSection.cs

using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.Specialized;
using CrossUI.Touch.Dialog.Elements;
using Cirrious.MvvmCross.Binding.Attributes;
using Cirrious.MvvmCross.Binding;
using Cirrious.CrossCore.Platform;
using Cirrious.CrossCore.WeakSubscription;

namespace mrtnkrstn.iOS.Views
{
	public class MvxBindableSection<TElementTemplate> : Section where TElementTemplate : Element, IBindableElement
	{
		private IEnumerable _itemsSource;
		private MvxNotifyCollectionChangedEventSubscription _subscription;

		public MvxBindableSection() : base()
		{
		}

		public MvxBindableSection(string caption) : base(caption)
		{
		}

		[MvxSetToNullAfterBinding]
		public IEnumerable ItemsSource
		{
			get { return _itemsSource; }
			set { SetItemsSource(value); }
		}

		protected virtual void SetItemsSource(IEnumerable value)
		{
			if (_itemsSource == value) {
				return;
			}

			if (_subscription != null) {
				_subscription.Dispose();
				_subscription = null;
			};

			_itemsSource = value;

			if (_itemsSource != null && !(_itemsSource is IList)) {
				MvxBindingTrace.Trace (MvxTraceLevel.Warning,
					"Binding to IEnumerable rather than IList - this can be inefficient, especially for large lists");
			}

			var newObservable = _itemsSource as INotifyCollectionChanged;
			if (newObservable != null) {
				_subscription = newObservable.WeakSubscribe (OnItemsSourceCollectionChanged);
			}

			NotifyDataSetChanged();
		}

		private void OnItemsSourceCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
		{
			NotifyDataSetChanged();
		}

		private void NotifyDataSetChanged()
		{
			var newElements = new List<Element>();
			if (_itemsSource != null) {
				foreach (var item in _itemsSource) {
					var element = Activator.CreateInstance<TElementTemplate>();

					element.DataContext = item;

					newElements.Add((Element) element);
				}
			}

			this.RemoveRange (0, Elements.Count);
			this.AddAll (newElements);

			var root = this.Parent as RootElement;

			if (root == null) {
				root = this.GetImmediateRootElement ();
			}

			if (root != null) {
				var tableView = root.GetContainerTableView ();
				tableView.ReloadData ();
			}
		}
	}
}