[英]How can I programmatically subscribe to all the events of an object?
我試圖訂閱由類似WPF GridView的第三方組件公開的所有事件,以便進行一些調試。 除了建議這可能不是調試它的最佳方式和類似的東西,我想知道是否可以這樣做。
對於路由事件,它的工作原理如下:
var type = tree.GetType();
do
{
var staticFields = type.GetFields(BindingFlags.Static | BindingFlags.Public);
foreach (var staticField in staticFields)
{
if (typeof(RoutedEvent).IsAssignableFrom(staticField.FieldType))
{
tree.AddHandler((RoutedEvent)staticField.GetValue(null), new RoutedEventHandler(OnRoutedEvent), true);
}
}
} while ((type = type.BaseType) != typeof(object)/* && type.FullName.StartsWith("Telerik")*/);
public void OnRoutedEvent(object sender, System.Windows.RoutedEventArgs e)
{
Debug.WriteLine(e.RoutedEvent.ToString());
}
但是,對於典型事件,這似乎不起作用:
var evts = tree.GetType().GetEvents();
foreach (var ev in evts)
{
ev.AddEventHandler(this, new EventHandler(OnEvent));
}
public void OnEvent(object sender, EventArgs e)
{
//..
}
因為它不喜歡委托是EventHandler而不是特殊類型,或者因為事件處理程序方法的簽名不包含專門的EventArgs類類型。
這可以以某種方式完成嗎?
------------ LATER EDIT ---------在所有這三種情況下(我的嘗試,ds27680的建議和Thomas Levesque的建議),AddEventHandler調用失敗了:
System.Reflection.TargetException occurred
Message=Object does not match target type.
Source=mscorlib
StackTrace:
at System.Reflection.RuntimeMethodInfo.CheckConsistency(Object target)
at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks)
at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
at System.Reflection.EventInfo.AddEventHandler(Object target, Delegate handler)
at Test.MainWindow..ctor() in c:\users\me\documents\visual studio 2010\Projects\Test\Test\MainWindow.xaml.cs:line 39
我想事件處理程序方法的簽名與EventArgs類型完全不匹配的事實是它失敗的原因......
您需要將委托“轉換”為適當的類型:
var evts = tree.GetType().GetEvents();
EventHandler tmp = OnEvent;
foreach (var ev in evts)
{
Delegate handler = Delegate.CreateDelegate(ev.EventHandlerType, tmp.Target, tmp.Method);
ev.AddEventHandler(this, handler);
}
您可以使用Delegate.CreateDelegate構造特定類型的事件。 值得一試。
你可以嘗試:
public class DebugHook
{
public static void OnEvent<EventArgsType>(object sender, EventArgsType eventArgs)
{
}
}
然后:
foreach (var ev in evts)
{
Type argsType = getEventArgsType(ev);
MethodInfo hook = typeof(DebugHook).GetMethod("OnEvent");
MethodInfo boundEventhandler = hook.MakeGenericMethod(new [] { argsType} );
Delegate handler = Delegate.CreateDelegate(ev.EventHandlerType, boundEventhandler);
ev.AddEventHandler(this, handler );
}
其中getEventArgs如下所示:
public Type getEventArgsType(EventInfo eventType)
{
Type t = eventType.EventHandlerType;
MethodInfo m = t.GetMethod("Invoke");
var parameters = m.GetParameters();
return parameters[1].ParameterType;
}
當然很多錯誤檢查/處理都丟失了......
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