[英]Weak References stays alive
我有一个接口:IRemoteDataChangedListener
public interface IRemoteDataChangedListener<TData>
{
void DataReceived(TData newData);
}
还有一个类,RealtimeEventService
public class RealtimeEventService : IRealtimeEventService
{
private readonly IEventListener listener;
private readonly List<Tuple<Type, WeakReference>> dataCreated;
public RealtimeEventService(IEventListener eventListener)
{
this.dataCreated = new List<Tuple<Type, WeakReference>>();
this.listener = eventListener;
this.listener.EventReceived += this.ListenerOnEventReceived;
}
private void ListenerOnEventReceived(EventMessage message)
{
Type type = message.GetType();
if (type == typeof(NotificationReadEventMessage))
{
this.DataChanged((NotificationReadEventMessage)message);
}
}
public void SubscribeDataChanged<TEventMessage>(IRemoteDataChangedListener<TEventMessage> dataChangedListener) where TEventMessage : EventMessage, new()
{
this.dataCreated.Add(Tuple.Create(typeof(TEventMessage), new WeakReference(dataChangedListener)));
}
internal void DataChanged<TKey>(TKey newData)
where TKey : class, new()
{
LoopAndFilter<TKey>(this.dataCreated, listener => listener.DataReceived(newData));
}
private static void LoopAndFilter<TKey>(ICollection<Tuple<Type, WeakReference>> collection,
Action<IRemoteDataChangedListener<TKey>> success) where TKey : class
{
foreach (var reference in collection.ToArray())
{
if (!reference.Item2.IsAlive)
{
collection.Remove(reference);
continue;
}
if (reference.Item1 != typeof(TKey))
continue;
success((IRemoteDataChangedListener<TKey>)reference.Item2.Target);
}
}
#endregion
}
每当我创建一个继承IRemoteDataChangedListener且NotificationReadEventMessage作为泛型参数的测试类,并使用此类的实例与SubscribeDataChanged()时,它就会很好地连接,并调用该方法。
问题是,当我将实例引用设置为null并运行GC.Collect()时,它应该为null,并且下次RealtimeEventService的LoopAndFilter方法运行时,它应该检测到它不再存活,并从中删除Weakreference名单。
但事实并非如此。 当我检查值(In LoopAndFilter)时,在测试中将实例引用设置为null后,该值仍显示为Alive为true。
现在我已经盯着这段代码好几个小时了,我根本找不到任何地方我都有强烈的参考资料......
有帮助吗?
@Edit:单元测试(使用Moq和Should库):
public class RealtimeEventServiceTests
{
[Fact]
public void VerifyWeakReferencesWorksAsIntended()
{
var eventListenerMock = new Mock<IEventListener>();
IRealtimeEventService service = new RealtimeEventService(eventListenerMock.Object);
bool called = false;
RemoteDataTest dataChangedListener = new RemoteDataTest();
dataChangedListener.Called += (sender, args) => called = true;
service.SubscribeDataChanged(dataChangedListener);
called.ShouldBeFalse();
((RealtimeEventService)service).DataChanged(new NotificationReadEventMessage());
called.ShouldBeTrue();
called = false;
dataChangedListener = null;
GC.Collect();
called.ShouldBeFalse();
((RealtimeEventService)service).DataChanged(new NotificationReadEventMessage());
called.ShouldBeFalse();
}
}
public class RemoteDataTest : IRemoteDataChangedListener<NotificationReadEventMessage>
{
public event EventHandler Called;
public void DataReceived(NotificationReadEventMessage newData)
{
if (Called != null) Called(this, null);
}
}
事实证明,当我回到家并在家编译它时,它运行得很好。 当我回到工作岗位时,它在那里工作得很好。
猜猜这只是那些在莫名其妙的时候神奇地消失的怪异虫子之一。 我很高兴摆脱它。
我确实接受了Ewan和Scott Chamberlain的建议,谢谢!
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