我已签了很多问题回答这里,但无法从其他类访问实例变量(我曾尝试this为例)广东话访问实例变量
#in file: view.py
class treeview():
def __init__(self):
....(no mention of row_num)
def viewer(self, booklist, act=-1):
row_num = len(treeview().full_list)
print(row_num) # prints the correct value, which is > 0
return row_num
#in main file
class Window(Gtk.ApplicationWindow):
def __init__(self, application, giofile=None):
self.TreeView = view.treeview()
def extract_data_from_cr(self, select_button):
print(self.TreeView.row_num)
给出错误:
AttributeError: 'treeview' object has no attribute 'row_num'
如果我尝试添加row_num
内树视图()为:
class treeview():
def __init__(self):
self.row_num = 0
def viewer(self, booklist, act=-1):
self.row_num = len(treeview().full_list)
print(self.row_num)
# return row_num
然后,print(self.TreeView.row_num)
在main
总是产生0
。
我无法找到这里出了什么问题。善良的帮助。
米奇的评论后 如果我定义ROW_NUM不调用树视图()再次为:
class treeview():
def __init__(self):
self.row_num = 0
def viewer(self, booklist, act=-1):
self.row_num = len(self.bookstore)
print(type(self.bookstore)) # <class 'gi.overrides.Gtk.ListStore'>
print(self.row_num) # 5 (expected for a particular case)
现在,调用def extract_data_from_cr
的时候,我期待这个数字:
def extract_data_from_cr(self, select_button):
print(self.TreeView.row_num) #is giving 0
A MCVE
$cat mcve.py
class classA():
def __init__(self):
self.row_num = 0
print("HiA")
def define(self):
la = ["A", "B", "C"]
self.row_num = len(la)
print(self.row_num) #prints 3 when get called from mcve2
return(self.row_num)
classA().define()
和
$cat mcve2.py
#!/usr/bin/python
import mcve
class classB():
def get_val(self):
self.MCVE = mcve.classA()
print("Hi2")
print(self.MCVE.row_num) #prints 0
classB().get_val()
结果:
python3 mcve2.py
HiA
3
HiA
Hi2
0
我知道。如果我从ClassB.get_val()
明确地拨打ClassA.define()
,我会得到期望的值。但我正在寻找转化它的价值(Result: line 2
)
我的错。实际上,在我的第二个例子中,'如果我尝试添加row_num'行,我已经在'treeview()'中添加了它,当从'main'调用时它总是产生0。示例已编辑。请看一看。 – BaRud