我的需求
我希望我们的内部标准产品在发生事情时触发不同的事件。在不同自定义解决方案的全局 asax 中,我想在需要时连接这些事件并做出反应。
现有模块
我一直在寻找 asp.net 的事件聚合器,但我不确定该使用什么。我读过关于 Prism 的文章,但似乎它针对的是 WPF/Silverlight 而不是 asp.net。
然后是这个家伙,他似乎已经将聚合器移植到他自己的版本中,独立于 WPF:http ://weblogs.asp.net/rashid/archive/2009/03/05/use-event-aggregator-to-使您的应用程序更可扩展.aspx
问题
有没有人体验过使用 asp.net 的事件聚合器?这是用于生产用途,所以我不喜欢使用网络上随机人提供的一些家庭编码聚合器:)
先感谢您。
编辑 1: 看起来, NServiceBus 有点矫枉过正。我创建了一个可以解决问题的 EventAggregator 类。
班上:
/// <summary>
/// A event aggregator.
/// </summary>
public class EventAggregator
{
/// <summary>The object to use when locking.</summary>
private readonly object _lock = new object();
/// <summary>Holder of registered event handlers</summary>
private readonly Dictionary<Type, List<object>> _handlers = new Dictionary<Type, List<object>>();
/// <summary>Registers the specified handler.</summary>
/// <typeparam name="T"></typeparam>
/// <param name="handler">The handler.</param>
public void Register<T>(EventHandler<T> handler) where T : EventArgs
{
lock (_lock)
{
if (!_handlers.ContainsKey(typeof (T)))
_handlers.Add(typeof (T), new List<object>());
_handlers[typeof (T)].Add(handler);
}
}
/// <summary>Publishes the specified event.</summary>
/// <typeparam name="T"></typeparam>
/// <param name="sender">The sender.</param>
/// <param name="eventToPublish">The event to publish.</param>
public void Publish<T>(object sender, T eventToPublish) where T : EventArgs
{
lock (_lock)
{
if (!_handlers.ContainsKey(typeof (T)))
return; // No listers for event
foreach (EventHandler<T> handler in _handlers[typeof (T)])
handler.Invoke(sender, eventToPublish);
}
}
}
一个事件类:
public class EntityDeleted : EventArgs
{
}
在全局 asax 中注册事件处理程序:
aggregator.Register<EntityDeleted>((s, e) => {
// Do stuff here
});
引发事件:
aggregator.Publish(this, new EntityDeleted());
编辑2:
这是我对感兴趣的人的单元测试:
/// <summary>
/// Unit tests for EventAggregator
/// </summary>
[TestClass]
public class EventAggregatorTest
{
/// <summary>Tests that no exceptions are thrown when calling an event with no handlers.</summary>
[TestMethod]
public void EmptyAggregatorTest()
{
var aggregator = new EventAggregator();
aggregator.Publish(this, new TestEventOne() { Property = "p1" });
}
/// <summary>Tests the aggregator using a single, registered handler.</summary>
[TestMethod]
public void SingleListenerTest()
{
var aggregator = new EventAggregator();
int calls = 0;
aggregator.Register<TestEventOne>((sender, e) =>
{
Assert.AreEqual("p1", e.Property);
calls ++;
});
Assert.AreEqual(0, calls);
aggregator.Publish(this, new TestEventOne(){Property = "p1"});
Assert.AreEqual(1, calls);
}
/// <summary>Tests the aggregator using multiple registered handlers.</summary>
[TestMethod]
public void MultipleListenersTest()
{
var aggregator = new EventAggregator();
int p1Calls = 0;
int p2Calls = 0;
aggregator.Register<TestEventOne>((sender, e) =>
{
Assert.AreEqual("p1", e.Property);
p1Calls++;
});
aggregator.Register<TestEventOne>((sender, e) =>
{
Assert.AreEqual("p1", e.Property);
p1Calls++;
});
aggregator.Register<TestEventTwo>((sender, e) =>
{
Assert.AreEqual("p2", e.Property);
p2Calls++;
});
Assert.AreEqual(0, p1Calls);
aggregator.Publish(this, new TestEventOne() { Property = "p1" });
Assert.AreEqual(2, p1Calls);
Assert.AreEqual(0, p2Calls);
aggregator.Publish(this, new TestEventTwo() { Property = "p2" });
Assert.AreEqual(1, p2Calls);
Assert.AreEqual(2, p1Calls);
}
}
/// <summary>
/// Dummy test event 1
/// </summary>
public class TestEventOne : EventArgs
{
public string Property { get; set; }
}
/// <summary>
/// Dummy test event 2
/// </summary>
public class TestEventTwo : EventArgs
{
public string Property { get; set; }
}
编辑 3:
感谢 Steven Robbins 指出聚合器不是线程安全的,我在 Publish 和 Register 方法中添加了锁定。