弱引用仍然存在

Question

我有一个接口：IRemoteDataChangedListener

public interface IRemoteDataChangedListener<TData>
{
    void DataReceived(TData newData);
}

还有一个class，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
}

每当我创建一个测试 class 继承 IRemoteDataChangedListener 并将 NotificationReadEventMessage 作为通用参数，并使用此 class 的一个实例与 SubscribeDataChanged() 时，它就会很好地连接起来，并且方法被调用。

问题是，当我将实例引用设置为 null 和运行 GC.Collect() 时，它应该为 null，而下一次 RealtimeEventService 的 LoopAndFilter 方法运行s，它应该检测到它不再存在，并从列表中删除 Weakreference。

然而事实并非如此。当我检查值（在 LoopAndFilter 中）时，在测试中将实例引用设置为 null 后，该值仍然显示为 Alive 为真。

现在我已经盯着这段代码看了好几个小时了，我根本找不到任何地方可以强烈引用 class...

有什么帮助吗？

@编辑：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);
    }
}

Answer 1

事实证明，当我回到家并在家编译它时，它运行就好了。当我回去工作时，它在那里也工作得很好。

我猜它只是那些在无法解释的时间神奇地消失的幽灵般的错误之一。我很高兴摆脱它。

我确实听取了 Ewan & Scott Chamberlain 的建议，非常感谢！

弱引用仍然存在

Weak References stays alive

c#

garbage-collection

weak-references