Refactored the library and upgraded to .NET Standard 2.1

* Removed the requirement to inherit your event classes from AsyncEventArgs
* Structs can now be used for event args
* Added AsyncEventHandlers without event args
* Updated samples

AsyncEventHandlers.Benchmarks/AsyncEventHandlers.Benchmarks.csproj

@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>net6.0</TargetFramework>
+    <TargetFramework>net7.0</TargetFramework>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
   </PropertyGroup>

AsyncEventHandlers.Benchmarks/Program.cs

@@ -11,33 +11,49 @@ public static void Main()
             BenchmarkRunner.Run<Program>();
         }
 
-        private static AsyncEventHandler<AsyncEventArgs> Struct_AsyncEventHandler = new AsyncEventHandler<AsyncEventArgs>();
-        private static event AsyncEventHandlerDelegate<AsyncEventArgs> Delegate_AsyncEventHandler;
+        private static AsyncEventHandler Struct_AsyncEventHandler = new AsyncEventHandler();
+        private static WeakAsyncEventHandler WeakAsyncEventHandler = new WeakAsyncEventHandler();
+        private static event AsyncEventHandlerDelegate<IAsyncEventArgs> Delegate_AsyncEventHandler;
+
+        private readonly List<object> eventSources = new List<object>();
 
         public Program()
         {
             for (int i = 0; i < 100; i++)
             {
+                eventSources.Add(new object());
+
+
                 Struct_AsyncEventHandler += Struct_AsyncEventHandler_Event;
+                WeakAsyncEventHandler.Register(eventSources[i], WeakAsyncEventHandler_Event);
                 Delegate_AsyncEventHandler += Delegate_AsyncEventHandler_Event;
             }
         }
 
-        private Task Struct_AsyncEventHandler_Event(object? sender, AsyncEventArgs e)
+        private Task Struct_AsyncEventHandler_Event(CancellationToken ct)
         {
             return Task.CompletedTask;
         }
 
-        private Task Delegate_AsyncEventHandler_Event(object? sender, AsyncEventArgs e)
+        private Task WeakAsyncEventHandler_Event(CancellationToken ct)
+        {
+            return Task.CompletedTask;
+        }
+
+        private Task Delegate_AsyncEventHandler_Event(object? sender, IAsyncEventArgs e)
         {
             return Task.CompletedTask;
         }
 
 
         private Task Struct_Call()
         {
-            var args = new AsyncEventArgs();
-            return Struct_AsyncEventHandler.InvokeAsync(this, args);
+            return Struct_AsyncEventHandler.InvokeAsync();
+        }
+
+        private Task Weak_Call()
+        {
+            return WeakAsyncEventHandler.InvokeAsync();
         }
 
         private ValueTask Delegate_Call()
@@ -53,24 +69,30 @@ public async Task Struct_Call_1()
         }
 
         [Benchmark]
-        public async Task Delegate_Call_1()
+        public async Task Weak_Call_1()
         {
-            await Delegate_Call();
+            await Weak_Call();
         }
 
         [Benchmark]
-        public async Task Struct_Call_100()
+        public async Task Delegate_Call_1()
         {
-            for (int i = 0; i < 100; i++)
-                await Struct_Call();
+            await Delegate_Call();
         }
 
-        [Benchmark]
-        public async Task Delegate_Call_100()
-        {
-            for (int i = 0; i < 100; i++)
-                await Delegate_Call();
-        }
+        //[Benchmark]
+        //public async Task Struct_Call_100()
+        //{
+        //    for (int i = 0; i < 100; i++)
+        //        await Struct_Call();
+        //}
+
+        //[Benchmark]
+        //public async Task Delegate_Call_100()
+        //{
+        //    for (int i = 0; i < 100; i++)
+        //        await Delegate_Call();
+        //}
     }
 
 }

AsyncEventHandlers/AsyncEvent.cs

@@ -0,0 +1,29 @@
+using System.Threading.Tasks;
+using System.Threading;
+
+namespace AsyncEventHandlers;
+
+/// <summary>
+/// The "action" delegate which should be supplied to the
+/// <see cref="AsyncEventHandler{TEventData}.Register(AsyncEvent{TEventData})"/> and <see cref="AsyncEventHandler{TEventData}.Unregister(AsyncEvent{TEventData})"/>
+/// methods.
+/// <para/>
+/// This shouldn't be used with the <see langword="event"/> keyword.
+/// </summary>
+/// <typeparam name="TEventData">Event data to pass to each subscriber.</typeparam>
+/// <param name="data">An object that contains the event data.</param>
+/// <param name="cancellationToken">The <see cref="CancellationToken"/> to communicate cancellation of the async operation.</param>
+/// <returns></returns>
+public delegate Task AsyncEvent<in TEventData>(TEventData data, CancellationToken cancellationToken);
+
+/// <summary>
+/// The "action" delegate which should be supplied to the
+/// <see cref="AsyncEventHandler.Register(AsyncEvent)"/> and <see cref="AsyncEventHandler.Unregister(AsyncEvent)"/>
+/// methods.
+/// <para/>
+/// This shouldn't be used with the <see langword="event"/> keyword.
+/// </summary>
+/// <typeparam name="TEventData">Event data to pass to each subscriber.</typeparam>
+/// <param name="cancellationToken">The <see cref="CancellationToken"/> to communicate cancellation of the async operation.</param>
+/// <returns></returns>
+public delegate Task AsyncEvent(CancellationToken cancellationToken);

AsyncEventHandlers/AsyncEventArgs.cs

@@ -1,15 +1,17 @@
-using System;
-using System.Collections.Generic;
-using System.Text;
-using System.Threading;
+using System.Threading;
 
-namespace AsyncEventHandlers
+namespace AsyncEventHandlers;
+
+/// <summary>
+/// The <see cref="CancellationToken"/> is automatically set.
+/// </summary>
+public interface IAsyncEventArgs
 {
-    /// <summary>
-    /// The <see cref="CancellationToken"/> is automatically set.
-    /// </summary>
-    public class AsyncEventArgs : EventArgs
-    {
-        public CancellationToken CancellationToken { get; internal set; }
-    }
+    CancellationToken CancellationToken { get; internal set; }
 }
+
+/// <inheritdoc cref="IAsyncEventArgs" />
+public class AsyncEventArgs : IAsyncEventArgs
+{
+    public CancellationToken CancellationToken { get; set; }
+}