有趣的问题,对我来说似乎是你不想一遍又一遍地写同样的东西。这就是为什么我宁愿选择单个通用组件,而不是哈希集或类似的东西。此外,由于表单实现通常基于线程,我使用并发字典。
这个解决方案可以通过几种不同的方式进行改进;最明显的是使处理更加通用,缺少0参数处理程序。我尽可能简单地保持了清晰度。也许我会在几天后在我的博客上发布更完整的内容;如果我这样做了,我会在这里分享信息。
我的解决方案有两个部分:(1)一个通用的钩子类和(2)表单中的实现。目前,该解决方案是懒惰的,例如,我将事件处理程序放在队列的末尾,而不是在队列的前面。您应该能够通过使用GetInvocationList或类似的东西来解决这个问题。
通用钩子类基本上是钩住事件并跟踪事件是否被调用:
public class EventHooks
{
private class EventHooksEquality : IEqualityComparer<Tuple<string, object>>
{
public bool Equals(Tuple<string, object> x, Tuple<string, object> y)
{
return x.Item1.Equals(y.Item1) && object.ReferenceEquals(x.Item2, y.Item2);
}
public int GetHashCode(Tuple<string, object> obj)
{
return obj.Item1.GetHashCode();
}
}
private ConcurrentDictionary<Tuple<string, object>, bool> called =
new ConcurrentDictionary<Tuple<string, object>, bool>(new EventHooksEquality());
private abstract class BaseHookHandler
{
protected BaseHookHandler(object container, string eventName, EventHooks hooks)
{
this.hooks = hooks;
this.container = container;
this.eventName = eventName;
}
protected string eventName;
protected object container;
protected EventHooks hooks;
}
private class HookHandler<T1> : BaseHookHandler
{
public HookHandler(object container, string eventName, EventHooks hooks)
: base(container, eventName, hooks)
{
}
public void Handle(T1 t1)
{
hooks.called.TryAdd(new Tuple<string, object>(eventName, container), true);
}
}
private class HookHandler<T1, T2> : BaseHookHandler
{
public HookHandler(object container, string eventName, EventHooks hooks)
: base(container, eventName, hooks)
{
}
public void Handle(T1 t1, T2 t2)
{
hooks.called.TryAdd(new Tuple<string, object>(eventName, container), true);
}
}
public void HookAll(object obj)
{
foreach (var eventHandler in obj.GetType().GetEvents())
{
Hook(obj, eventHandler.Name);
}
}
public void Hook(object obj, string eventHandler)
{
if (obj == null)
{
throw new Exception("You have to initialize the object before hooking events.");
}
var field = obj.GetType().GetEvent(eventHandler);
var delegateInvoke = field.EventHandlerType.GetMethod("Invoke");
Type[] parameterTypes = delegateInvoke.GetParameters().Select((a) => (a.ParameterType)).ToArray();
var genericHandler = Type.GetType(GetType().FullName + "+HookHandler`" + parameterTypes.Length);
var handlerType = genericHandler.MakeGenericType(parameterTypes);
var handlerObject = Activator.CreateInstance(handlerType, obj, eventHandler, this);
var handler = handlerType.GetMethod("Handle");
var del = Delegate.CreateDelegate(field.EventHandlerType, handlerObject, handler);
field.AddEventHandler(obj, del);
}
public bool IsCalled(object obj, string eventHandler)
{
return called.ContainsKey(new Tuple<string, object>(eventHandler, obj));
}
}
在类中的使用方法如下(示例):
public Form1()
{
InitializeComponent();
hooks.HookAll(this);
hooks.Hook(button1, "Click");
}
private EventHooks hooks = new EventHooks();
private void Form1_Load(object sender, EventArgs e)
{
}
private void button1_Click(object sender, EventArgs e)
{
this.textBox1.Text =
string.Format("Load: {0}\r\nClick: {1}\r\nButton click: {2}\r\n",
hooks.IsCalled(this, "Load"),
hooks.IsCalled(this, "Click"),
hooks.IsCalled(button1, "Click"));
}