How about the following in HttpModule.Init:
IList<EventHandler> l = GetCurrentDelegatesForEvent(context, "Error", "EventErrorRecorded", "Events");
// Remove existing handlers.
foreach (EventHandler eh in l)
{
context.Error -= eh;
}
// Add our handler first.
context.Error += new EventHandler(HandleApplicationError);
// Add removed handlers after ours.
foreach (EventHandler eh in l)
{
context.Error += eh;
}
and
/// <summary>
/// Use reflection to obtain list of current delegates for an event.
/// </summary>
/// <param name="context"></param>
/// <param name="eventName"></param>
/// <param name="eventObjectFieldName"></param>
/// <param name="eventsPropertyName"></param>
/// <returns></returns>
private IList<EventHandler> GetCurrentDelegatesForEvent(HttpApplication context, string eventName, string eventObjectFieldName, string eventsPropertyName)
{
IList<EventHandler> l = new List<EventHandler>();
try
{
BindingFlags bf = BindingFlags.IgnoreCase | BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Static;
Type dt = null;
Type t = context.GetType();
foreach (EventInfo ei in t.GetEvents(bf))
{
if (ei.Name == eventName)
{
dt = ei.DeclaringType;
break;
}
}
if (dt != null)
{
FieldInfo fiEER = dt.GetField(eventObjectFieldName, bf);
if (fiEER != null)
{
object eer = fiEER.GetValue(context);
if (eer != null)
{
PropertyInfo piEvents = dt.GetProperty(eventsPropertyName, bf);
if (piEvents != null)
{
object ehlo = piEvents.GetValue(context, null);
if (ehlo != null)
{
EventHandlerList ehl = ehlo as EventHandlerList;
if (ehl != null)
{
object handler = ehl[eer];
if (handler != null)
{
EventHandler mHandler = handler as EventHandler;
if (mHandler != null)
{
foreach (EventHandler eh in mHandler.GetInvocationList())
{
l.Add(eh);
}
}
}
}
}
}
}
}
}
}
catch (Exception ex)
{
Log.Error("Failure obtaining current delegates for Error Event", ex);
}
return l;
}
