PropertyAddClassHandlerBenchmarks.cs

using BenchmarkDotNet.Attributes;

namespace Avalonia.Benchmarks.Data
{
    [MemoryDiagnoser, InProcess]
    public class PropertyAddClassHandlerBenchmarks
    {
        private const int Iterations = 100;

        [Benchmark(Baseline = true)]
        public void AddClassHandler()
        {
            var target = new AddClassHandlerTest();

            for (var i = 0; i < Iterations; ++i)
                target.Foo = i;
        }

        [Benchmark]
        public void OnPropertyChanged()
        {
            var target = new OnPropertyChangedTest();

            for (var i = 0; i < Iterations; ++i)
                target.Foo = i;
        }

        private class AddClassHandlerTest : AvaloniaObject
        {
            public static StyledProperty<int> FooProperty =
                AvaloniaProperty.Register<AddClassHandlerTest, int>("Foo");

            static AddClassHandlerTest()
            {
                FooProperty.Changed.AddClassHandler<AddClassHandlerTest, int>((x, e) => x.FooChanged(e));
            }

            public int Foo
            {
                get => GetValue(FooProperty);
                set => SetValue(FooProperty, value);
            }

            public int LastValue { get; private set; }

            private void FooChanged(AvaloniaPropertyChangedEventArgs<int> e) => LastValue = e.NewValue.Value;
        }


        private class OnPropertyChangedTest : AvaloniaObject
        {
            public static StyledProperty<int> FooProperty =
                AvaloniaProperty.Register<AddClassHandlerTest, int>("Foo");

            public int Foo
            {
                get => GetValue(FooProperty);
                set => SetValue(FooProperty, value);
            }

            public int LastValue { get; private set; }

            protected override void OnPropertyChanged<T>(AvaloniaPropertyChangedEventArgs<T> change)
            {
                base.OnPropertyChanged(change);

                if (change.Property == FooProperty)
                    LastValue = change.NewValue.GetValueOrDefault<int>();
            }
        }
    }
}