Add AddRange for NotifyingCollection, expose all elements under a Lay…

…outRoot

MagicUI/Behaviours/LayoutOrchestrator.cs

@@ -16,6 +16,8 @@ internal class LayoutOrchestrator : MonoBehaviour
 
         public bool shouldRenderDebugBounds = false;
 
+        public IEnumerable<ArrangableElement> Elements => elements.AsReadOnly();
+
         /// <summary>
         /// Registers an element in layout for arrangement and later lookup
         /// </summary>

MagicUI/Core/LayoutRoot.cs

@@ -30,6 +30,11 @@ public class LayoutRoot
         /// </summary>
         public GameObject Canvas { get => rootCanvas; }
 
+        /// <summary>
+        /// A read-only collection of elements registered to this layout
+        /// </summary>
+        public IEnumerable<ArrangableElement> Elements => layoutOrchestrator.Elements;
+
         /// <summary>
         /// A predicate that determines whether the layout should be visible. By default (i.e. when there is no condition), the layout is
         /// always visible.

MagicUI/Core/NotifyingCollection.cs

@@ -48,6 +48,19 @@ public void Add(T item)
             actionOnChange.Notify(owner);
         }
 
+        /// <summary>
+        /// Convenience method to add several items at once
+        /// </summary>
+        /// <param name="items">The items to add to the collection</param>
+        public void AddRange(IEnumerable<T> items)
+        {
+            foreach (T item in items)
+            {
+                this.items.Add(item);
+            }
+            actionOnChange.Notify(owner);
+        }
+
         /// <inheritdoc/>
         public void Clear()
         {

MagicUI/Elements/GridLayout.cs

@@ -95,14 +95,14 @@ public class GridLayout : Layout
         /// Definition of the number of rows, their sizes, and their types. By default this is empty. If the grid is measured
         /// with empty row definitions, one will be added for you with a minimum height of 0px.
         /// </summary>
-        public ICollection<GridDimension> RowDefinitions => rowDefs;
+        public NotifyingCollection<GridDimension> RowDefinitions => rowDefs;
 
         private NotifyingCollection<GridDimension> colDefs;
         /// <summary>
         /// Definition of the number of columns, their sizes, and their types. By default this is empty. If the grid is measured
         /// with empty column definitions, one will be added for you with a minimum height of 0px.
         /// </summary>
-        public ICollection<GridDimension> ColumnDefinitions => colDefs;
+        public NotifyingCollection<GridDimension> ColumnDefinitions => colDefs;
 
         private float minWidth = 0;
         /// <summary>