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using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using Autofac;
namespace DotNetDesignPatternDemos.Behavioral.Observer.ContainerWireup
{
public interface IEvent {}
public interface ISend<TEvent> where TEvent : IEvent
{
event EventHandler<TEvent> Sender;
}
public interface IHandle<TEvent> where TEvent : IEvent
{
void Handle(object sender, TEvent args);
}
public class ButtonPressedEvent : IEvent
{
public int NumberOfClicks;
}
public class Button : ISend<ButtonPressedEvent>
{
public event EventHandler<ButtonPressedEvent> Sender;
public void Fire(int clicks)
{
Sender?.Invoke(this, new ButtonPressedEvent
{
NumberOfClicks = clicks
});
}
}
public class Logging : IHandle<ButtonPressedEvent>
{
public void Handle(object sender, ButtonPressedEvent args)
{
Console.WriteLine(
$"Button clicked {args.NumberOfClicks} times");
}
}
class Program
{
static void Main(string[] args)
{
var cb = new ContainerBuilder();
var ass = Assembly.GetExecutingAssembly();
// register publish interfaces
cb.RegisterAssemblyTypes(ass)
.AsClosedTypesOf(typeof(ISend<>))
.SingleInstance();
// register subscribers
cb.RegisterAssemblyTypes(ass)
.Where(t =>
t.GetInterfaces()
.Any(i =>
i.IsGenericType &&
i.GetGenericTypeDefinition() == typeof(IHandle<>)))
.OnActivated(act =>
{
var instanceType = act.Instance.GetType();
var interfaces = instanceType.GetInterfaces();
foreach (var i in interfaces)
{
if (i.IsGenericType && i.GetGenericTypeDefinition() == typeof(IHandle<>))
{
var arg0 = i.GetGenericArguments()[0];
var senderType = typeof(ISend<>).MakeGenericType(arg0);
var allSenderTypes = typeof(IEnumerable<>).MakeGenericType(senderType);
var allServices = act.Context.Resolve(allSenderTypes);
foreach (var service in (IEnumerable) allServices)
{
var eventInfo = service.GetType().GetEvent("Sender");
var handleMethod = instanceType.GetMethod("Handle");
var handler = Delegate.CreateDelegate(
eventInfo.EventHandlerType, null, handleMethod);
eventInfo.AddEventHandler(service, handler);
}
}
}
})
.SingleInstance()
.AsSelf();
var container = cb.Build();
var button = container.Resolve<Button>();
var logging = container.Resolve<Logging>();
button.Fire(1);
button.Fire(2);
}
}
}
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