feature: Adds OnItemRefreshed extension method for SourceList and SourceCache

src/DynamicData.Tests/Cache/OnItemFixture.cs

@@ -22,6 +22,22 @@ public void OnItemAddCalled()
         Assert.True(called);
     }
 
+    [Fact]
+    public void OnItemRefreshedCalled()
+    {
+        var called = false;
+        var source = new SourceCache<Person, int>(x => x.Age);
+
+        var person = new Person("A", 1);
+        source.AddOrUpdate(person);
+
+        source.Connect().AutoRefresh(x=>x.Age).OnItemRefreshed(_ => called = true).Subscribe();
+
+        person.Age += 1;
+
+        Assert.True(called);
+    }
+
     [Fact]
     public void OnItemRemovedCalled()
     {

src/DynamicData.Tests/List/OnItemFixture.cs

@@ -0,0 +1,54 @@
+using System;
+
+using DynamicData.Tests.Domain;
+
+using Xunit;
+
+namespace DynamicData.Tests.List;
+
+public class OnItemFixture
+{
+    [Fact]
+    public void OnItemAddCalled()
+    {
+        var called = false;
+        var source = new SourceList<Person>();
+
+        source.Connect().OnItemAdded(_ => called = true).Subscribe();
+
+        var person = new Person("A", 1);
+
+        source.Add(person);
+        Assert.True(called);
+    }
+
+    [Fact]
+    public void OnItemRefreshedCalled()
+    {
+        var called = false;
+        var source = new SourceList<Person>();
+
+        var person = new Person("A", 1);
+        source.Add(person);
+
+        source.Connect().AutoRefresh(x=>x.Age).OnItemRefreshed(_ => called = true).Subscribe();
+
+        person.Age += 1;
+
+        Assert.True(called);
+    }
+
+    [Fact]
+    public void OnItemRemovedCalled()
+    {
+        var called = false;
+        var source = new SourceList<Person>();
+
+        source.Connect().OnItemRemoved(_ => called = true).Subscribe();
+
+        var person = new Person("A", 1);
+        source.Add(person);
+        source.Remove(person);
+        Assert.True(called);
+    }
+}

src/DynamicData/Cache/ObservableCacheEx.cs

@@ -4,19 +4,14 @@
 
 #pragma warning disable SA1137
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.ComponentModel;
 using System.Diagnostics.CodeAnalysis;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reactive;
 using System.Reactive.Concurrency;
 using System.Reactive.Disposables;
 using System.Reactive.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 
 using DynamicData.Binding;
 using DynamicData.Cache.Internal;
@@ -2824,6 +2819,37 @@ public static IObservable<IChangeSet<TObject, TKey>> OnItemAdded<TObject, TKey>(
         return source.Do(changes => changes.Where(c => c.Reason == ChangeReason.Add).ForEach(c => addAction(c.Current)));
     }
 
+    /// <summary>
+    /// Callback for each item as and when it is being refreshed in the stream.
+    /// </summary>
+    /// <typeparam name="TObject">The type of the object.</typeparam>
+    /// <typeparam name="TKey">The type of the key.</typeparam>
+    /// <param name="source">The source.</param>
+    /// <param name="refreshAction">The refresh action.</param>
+    /// <returns>An observable which emits a change set with items being added.</returns>
+    public static IObservable<IChangeSet<TObject, TKey>> OnItemRefreshed<TObject, TKey>(this IObservable<IChangeSet<TObject, TKey>> source, Action<TObject> refreshAction)
+        where TKey : notnull
+    {
+        Action<TObject> refreshAction2 = refreshAction;
+        if (source == null)
+        {
+            throw new ArgumentNullException(nameof(source));
+        }
+
+        if (refreshAction2 == null)
+        {
+            throw new ArgumentNullException(nameof(refreshAction));
+        }
+
+        return source.Do(delegate(IChangeSet<TObject, TKey> changes)
+        {
+            changes.Where((Change<TObject, TKey> c) => c.Reason == ChangeReason.Refresh).ForEach(delegate(Change<TObject, TKey> c)
+            {
+                refreshAction2(c.Current);
+            });
+        });
+    }
+
     /// <summary>
     /// Callback for each item as and when it is being removed from the stream.
     /// </summary>

src/DynamicData/List/ObservableListEx.cs

@@ -2,17 +2,13 @@
 // Roland Pheasant licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for full license information.
 
-using System;
-using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.ComponentModel;
-using System.Linq;
 using System.Linq.Expressions;
 using System.Reactive;
 using System.Reactive.Concurrency;
 using System.Reactive.Disposables;
 using System.Reactive.Linq;
-using System.Threading.Tasks;
 
 using DynamicData.Binding;
 using DynamicData.Cache.Internal;
@@ -333,6 +329,7 @@ public static IObservable<IChangeSet<T>> Bind<T>(this IObservable<IChangeSet<T>>
     }
 
 #if SUPPORTS_BINDINGLIST
+
     /// <summary>
     /// Binds a clone of the observable change set to the target observable collection.
     /// </summary>
@@ -1118,6 +1115,35 @@ public static IObservable<IChangeSet<T>> OnItemAdded<T>(this IObservable<IChange
         return new OnBeingAdded<T>(source, addAction).Run();
     }
 
+    /// <summary>
+    /// Callback for each item as and when it is being refreshed in the stream.
+    /// </summary>
+    /// <typeparam name="TObject">The type of the object.</typeparam>
+    /// <param name="source">The source.</param>
+    /// <param name="refreshAction">The refresh action.</param>
+    /// <returns>An observable which emits a change set with items being added.</returns>
+    public static IObservable<IChangeSet<TObject>> OnItemRefreshed<TObject>(this IObservable<IChangeSet<TObject>> source, Action<TObject> refreshAction)
+    {
+        Action<TObject> refreshAction2 = refreshAction;
+        if (source == null)
+        {
+            throw new ArgumentNullException(nameof(source));
+        }
+
+        if (refreshAction2 == null)
+        {
+            throw new ArgumentNullException(nameof(refreshAction));
+        }
+
+        return source.Do(delegate(IChangeSet<TObject> changes)
+        {
+            changes.Where((Change<TObject> c) => c.Reason == ListChangeReason.Refresh).ForEach(delegate(Change<TObject> c)
+            {
+                refreshAction2(c.Item.Current);
+            });
+        });
+    }
+
     /// <summary>
     /// Callback for each item as and when it is being removed from the stream.
     /// </summary>