有人问过c#类似的问题:Is using AddHandler functionally different from Event += Method?
但是我的研究给出了不同的结果,反对那里给出的答案。
我在IronPython中根据http://manaspatnaik.com/blog/index.php/technology/wpf/routed-event-in-wpf-introduction/244
写了一个小小的演示以下是代码:
import wpf
from System.Windows import Application, Window
from System.Windows.Media import Brushes
from System.Windows import EventManager
from System.Windows import RoutedEventHandler, RoutedEventArgs
class MyWindow(Window):
def __init__(self):
wpf.LoadComponent(self, 'WpfTestApplication1.xaml')
#self.MyPanel.MouseMove += self.Mouse_Move_Handler
delegate = RoutedEventHandler(self.Mouse_Move_Handler)
self.routed_events = EventManager.GetRoutedEvents()
mouse_move_event = [ev for ev in self.routed_events if ev.Name =='MouseMove'][0]
self.MyPanel.AddHandler(mouse_move_event,delegate)
self.MyPanel.MouseLeave += self.Mouse_Leave_Handler
self.MyButton.MouseMove += self.Button_Handler
self.MyButton.Click += self.Button_Click
self.MyButton.Click += self.Button_Click
def Mouse_Move_Handler(self, sender, e):
self.MyPanel.Background = Brushes.Red
self.MyLabel.Content = 'Inside Panel'
def Mouse_Leave_Handler(self,sender,e):
self.MyPanel.Background = Brushes.Cyan
self.MyLabel.Content = 'Outside Panel'
def Button_Handler(self, sender, e):
self.MyPanel.Background = Brushes.DarkBlue
e.Handled = True
def Button_Click(self, sender, event):
self.MyLabel.Background = Brushes.SaddleBrown
if __name__ == '__main__':
win = MyWindow()
Application().Run(win)
现在行为似乎完全一样。 AddHandler例程有原因吗? 也有人可能会考虑到这样做:
AddHandler(self.MouseMove,delegate) or AddHandler(Window.MouseMove,delegate)
导致错误:
ArgumentTypeException was unhandled by user code
expected RoutedEvent, got BoundEvent
任何人都可以澄清情况吗?区别在哪里?
编辑:通过使用Control.MouseMoveEvent而不是从EventManager中提取mouse_move_event,可以通过这两行来减少代码:
#self.routed_events = EventManager.GetRoutedEvents()
#mouse_move_event = [ev for ev in self.routed_events if ev.Name =='MouseMove'][0]
我真的看不出任何差异。