Avalonia/src/Avalonia.Base/Utilities/IWeakEventSubscriber.cs

using System;

namespace Avalonia.Utilities;

/// <summary>
/// Defines a listener to a event subscribed vis the <see cref="WeakEvent{TTarget, TEventArgs}"/>.
/// </summary>
/// <typeparam name="TEventArgs">The type of the event arguments.</typeparam>
public interface IWeakEventSubscriber<in TEventArgs> where TEventArgs : EventArgs
{
    void OnEvent(object? sender, WeakEvent ev, TEventArgs e);
}