![](/img/trans.png)
[英]Why can't you omit the arguments to super if you add *args in __init__ definition?
[英]Why can't you call object attributes within __init__?
我试图理解为什么您可以在类的方法中调用对象的属性,但不能在其构造函数中调用。 例如:
class Panel1(wx.Panel):
#include Frame in the constructor
def __init__(self, parent, frame):
wx.Panel.__init__(self, parent)
#set up so objects assigned in Frame (and it's children) can be called
self.frame = frame
button = wx.Button(self, label='Test')
#button.Bind(wx.EVT_BUTTON, lambda event: self.onButton(event))
button.Bind(wx.EVT_BUTTON, self.onButton)
pprint(vars(self.frame))
def onButton(self, event):
print("Button pressed.")
pprint(vars(self.frame))
#the following fails in the constructor as panel2 for some reason is not callable
a = self.frame.panel2.a
print("123: " + str(a))
有人可以给我一个链接来解释为什么在构造函数中这是不可能的吗?
谢谢!
*****编辑****
以下是有助于更好地解释我的问题的功能代码。 如果您尝试通过 Panel1 构造函数中的父级调用 Panel2 属性,则会失败。 但是在 Panel1 的 onButton 方法中完成时它工作正常。 我想了解为什么。
import wx
from pprint import pprint
class Panel1(wx.Panel):
#include Frame in the constructor
def __init__(self, parent, frame):
wx.Panel.__init__(self, parent)
self.frame = frame
self.strPanel1 = "Panel1 string"
self.intPanel1 = 0
button = wx.Button(self, label='Test')
button.Bind(wx.EVT_BUTTON, self.onButton)
self.textbox = wx.TextCtrl(self)
sizer = wx.BoxSizer(wx.VERTICAL)
self.SetSizer(sizer)
sizer.Add(self.textbox, 0, wx.ALL, 5)
sizer.Add(button, 0, wx.ALL, 5)
#pprint self.frame attributes fail here
def onButton(self, event):
#but not here!?!
print("Panel1 button pressed.")
pprint(vars(self.frame))
Panel2str = self.frame.panel2.strPanel2
print(Panel2str)
Panel2int = self.frame.panel2.intPanel2
print(str(Panel2int))
#Panel2 button press counter
self.frame.panel2.intPanel2 += 1
self.frame.panel2.trigger()
def trigger(self):
print("Panel1 has been triggered")
class Panel2(wx.Panel):
#include Frame in the constructor
def __init__(self, parent, frame):
wx.Panel.__init__(self, parent)
self.frame = frame
self.strPanel2 = "Panel2 string"
self.intPanel2 = 0
button = wx.Button(self, label='Test')
button.Bind(wx.EVT_BUTTON, self.onButton)
self.textbox = wx.TextCtrl(self)
sizer = wx.BoxSizer(wx.VERTICAL)
self.SetSizer(sizer)
sizer.Add(self.textbox, 0, wx.ALL, 5)
sizer.Add(button, 0, wx.ALL, 5)
#pprint self.frame attributes fail here
def onButton(self, event):
#but not here!?!
print("Panel2 button pressed.")
pprint(vars(self.frame))
Panel1str = self.frame.panel1.strPanel1
print(Panel1str)
Panel1int = self.frame.panel1.intPanel1
print(str(Panel1int))
#Panel1 button press counter
self.frame.panel1.intPanel1 += 1
self.frame.panel1.trigger()
def trigger(self):
print("Panel2 has been triggered")
class Frame(wx.Frame):
def __init__(self):
wx.Frame.__init__(self, None, title="My Frame")
#Spliiting the frame
splitter = wx.SplitterWindow(self)
#Send frame to children
self.panel1 = Panel1(splitter, self)
self.panel2 = Panel2(splitter, self)
splitter.SplitVertically(self.panel1, self.panel2, 0)
splitter.SetMinimumPaneSize(200)
sizer = wx.BoxSizer(wx.VERTICAL)
sizer.Add(splitter, 1, wx.EXPAND)
self.SetSizer(sizer)
if __name__ == '__main__':
app = wx.App()
frame = Frame()
frame.Show()
frame.Centre()
app.MainLoop()
以下是有助于更好地解释我的问题的功能代码。 如果您尝试通过 Panel1 构造函数中的父级调用 Panel2 属性,则会失败。
它失败了,因为在调用Panel1.__init__
, frame.panel2
尚未设置。 看看你的Frame
类:
class Frame(wx.Frame):
def __init__(self):
wx.Frame.__init__(self, None, title="My Frame")
#Spliiting the frame
splitter = wx.SplitterWindow(self)
#Send frame to children
self.panel1 = Panel1(splitter, self)
self.panel2 = Panel2(splitter, self)
...
当您的Panel1
初始化时, panel2
尚未设置。 只有在Panel1
完成初始化并已分配给frame.panel1
才会设置它。 如果您绝对需要将panel2
访问到Panel1.__init__
,那么您可以进行设置,以便您的Panel1
处理它。 例如:
class Panel1:
def __init__(self, frame):
# Initialize panel2 and assign it to our frame
frame.panel2 = Panel2(frame)
# Now we can do whatever with panel2
frame.panel2
class Panel2:
def __init__(self, frame):
pass
class Frame:
def __init__(self):
# This initialize panel1, and internally initialize panel2
self.panel1 = Panel1(self)
frame = Frame()
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.