Merge pull request #986 from Caliburn-Micro/alert-fix-72

Refactor AttachedCollection for readability and clarity

Author: vb2ae

src/Caliburn.Micro.Platform/Platforms/Maui/AttachedCollection.cs

@@ -1,6 +1,5 @@
-namespace Caliburn.Micro.Maui 
+namespace Caliburn.Micro.Maui
 {
-    using System;
     using System.Collections.Specialized;
     using System.Linq;
     using global::Microsoft.Maui.Controls;
@@ -10,7 +9,7 @@
     /// </summary>
     /// <typeparam name="T">The type of item in the attached collection.</typeparam>
     public class AttachedCollection<T> : BindableCollection<BindableObject>, IAttachedObject
-        where T : BindableObject, IAttachedObject 
+        where T : BindableObject, IAttachedObject
     {
         private BindableObject associatedObject;
 
@@ -27,45 +26,51 @@ public void Attach(BindableObject dependencyObject)
         /// <summary>
         /// Detaches the collection.
         /// </summary>
-        public void Detach() {
+        public void Detach()
+        {
             this.OfType<IAttachedObject>().Apply(x => x.Detach());
             associatedObject = null;
         }
 
         /// <summary>
         /// The currently attached object.
         /// </summary>
-        public BindableObject AssociatedObject {
+        public BindableObject AssociatedObject
+        {
             get { return associatedObject; }
         }
 
         /// <summary>
         /// Called when an item is added from the collection.
         /// </summary>
         /// <param name="item">The item that was added.</param>
-        protected virtual void OnItemAdded(BindableObject item) {
-            if (associatedObject != null) {
-                if (item is IAttachedObject)
-                    ((IAttachedObject) item).Attach(associatedObject);
+        protected virtual void OnItemAdded(BindableObject item)
+        {
+            if (associatedObject != null && item is IAttachedObject attached)
+            {
+                attached.Attach(associatedObject);
             }
         }
 
         /// <summary>
         /// Called when an item is removed from the collection.
         /// </summary>
         /// <param name="item">The item that was removed.</param>
-        protected virtual void OnItemRemoved(BindableObject item) {
-            if (item is IAttachedObject) {
-                if (((IAttachedObject) item).AssociatedObject != null)
-                    ((IAttachedObject) item).Detach();
+        protected virtual void OnItemRemoved(BindableObject item)
+        {
+            if (item is IAttachedObject attached &&
+                attached.AssociatedObject != null)
+            {
+                attached.Detach();
             }
         }
 
         /// <summary>
         /// Raises the <see cref = "E:System.Collections.ObjectModel.ObservableCollection`1.CollectionChanged" /> event with the provided arguments.
         /// </summary>
         /// <param name = "e">Arguments of the event being raised.</param>
-        protected override void OnCollectionChanged(NotifyCollectionChangedEventArgs e) {
+        protected override void OnCollectionChanged(NotifyCollectionChangedEventArgs e)
+        {
             base.OnCollectionChanged(e);
 
             if (e.OldItems != null)

src/Caliburn.Micro.Platform/Platforms/Xamarin.Forms/AttachedCollection.cs

@@ -1,6 +1,5 @@
 namespace Caliburn.Micro.Xamarin.Forms
 {
-    using System;
     using System.Collections.Specialized;
     using System.Linq;
     using global::Xamarin.Forms;
@@ -10,7 +9,7 @@
     /// </summary>
     /// <typeparam name="T">The type of item in the attached collection.</typeparam>
     public class AttachedCollection<T> : BindableCollection<BindableObject>, IAttachedObject
-        where T : BindableObject, IAttachedObject 
+        where T : BindableObject, IAttachedObject
     {
         private BindableObject associatedObject;
 
@@ -27,44 +26,50 @@ public void Attach(BindableObject dependencyObject)
         /// <summary>
         /// Detaches the collection.
         /// </summary>
-        public void Detach() {
+        public void Detach()
+        {
             this.OfType<IAttachedObject>().Apply(x => x.Detach());
             associatedObject = null;
         }
 
         /// <summary>
         /// The currently attached object.
         /// </summary>
-        public BindableObject AssociatedObject {
+        public BindableObject AssociatedObject
+        {
             get { return associatedObject; }
         }
 
         /// <summary>
         /// Called when an item is added from the collection.
         /// </summary>
         /// <param name="item">The item that was added.</param>
-        protected virtual void OnItemAdded(BindableObject item) {
-            if (associatedObject != null) {
-                if (item is IAttachedObject)
-                    ((IAttachedObject) item).Attach(associatedObject);
+        protected virtual void OnItemAdded(BindableObject item)
+        {
+            if (associatedObject != null && item is IAttachedObject attached)
+            {
+                attached.Attach(associatedObject);
             }
         }
 
         /// <summary>
         /// Called when an item is removed from the collection.
         /// </summary>
         /// <param name="item">The item that was removed.</param>
-        protected virtual void OnItemRemoved(BindableObject item) {
-            if (item is IAttachedObject && ((IAttachedObject) item).AssociatedObject != null) {
-                ((IAttachedObject) item).Detach();
+        protected virtual void OnItemRemoved(BindableObject item)
+        {
+            if (item is IAttachedObject attached && attached.AssociatedObject != null)
+            {
+                attached.Detach();
             }
         }
 
         /// <summary>
         /// Raises the <see cref = "E:System.Collections.ObjectModel.ObservableCollection`1.CollectionChanged" /> event with the provided arguments.
         /// </summary>
         /// <param name = "e">Arguments of the event being raised.</param>
-        protected override void OnCollectionChanged(NotifyCollectionChangedEventArgs e) {
+        protected override void OnCollectionChanged(NotifyCollectionChangedEventArgs e)
+        {
             base.OnCollectionChanged(e);
 
             if (e.OldItems != null)