Start modernization

Application/Data/RealmObservableCollection.cs

@@ -0,0 +1,29 @@
+using Realms;
+using System.Collections.ObjectModel;
+using System.Collections.Specialized;
+
+namespace FeedCenter.Data
+{
+    public class RealmObservableCollection<T> : ObservableCollection<T> where T : IRealmObject
+    {
+        private readonly Realm _realm;
+
+        public RealmObservableCollection(Realm realm) : base(realm.All<T>())
+        {
+            _realm = realm;
+        }
+
+        protected override void OnCollectionChanged(NotifyCollectionChangedEventArgs e)
+        {
+            if (e.OldItems != null)
+                foreach (T item in e.OldItems)
+                    _realm.Remove(item);
+
+            if (e.NewItems != null)
+                foreach (T item in e.NewItems)
+                    _realm.Add(item);
+
+            base.OnCollectionChanged(e);
+        }
+    }
+}