我创建了几个列表框小部件，在其中选择一个项目，然后按下面的按钮将项目移动到另一个。
这非常合适 - 但我想重复使用容器框架，因为2个框架的布局是相同的（除了标题标签和按下按钮时的功能）。所以我将除按钮功能之外的所有代码移动到类“ColumnSelector”。
但是要将数据从一个“ColumnSelector”移动到另一个“ColumnSelector”，我需要引用实例中的列表框。以下是我想做的结构，但我不确定这是否可行。
我尝试过其他一些方法，例如在ColumnSelector类之外创建列表框并将其传递出去，但我也遇到了问题。
在其他类的实例中引用小部件的最佳方法是什么？
# Data to be included in second listbox widget
startingSelection = ('Argentina', 'Australia', 'Belgium', 'Brazil', 'Canada', 'China', 'Denmark')
# Two functions performed by the ColumnSelectors
def removeSelected(*args):
idxs = selectedColumns.listBox.curselection() # <- Does not reference correctly
if len(idxs)>=1:
for n in reversed(range(len(idxs))):
idx = int(idxs[n])
item = selectedColumns.listBox.get(idx)
selectedColumns.listBox.delete(idx)
availableColumns.listBox.insert(availableColumns.listBox.size(), item)
def addSelected(*args):
idxs = availableColumns.listBox.curselection() #<- Does not reference correctly
if len(idxs)>=1:
for n in reversed(range(len(idxs))):
idx = int(idxs[n])
item = availableColumns.listBox.get(idx)
availableColumns.listBox.delete(idx)
selectedColumns.listBox.insert(selectedColumns.listBox.size(), item)
# Create ColumnSelectors, pass heading title and function to perform
selectedColumns = ColumnSelector(self, "Columns to include in export", (), removeSelected).grid(column=0, row=0, sticky=(N,W))
availableColumns = ColumnSelector(self, "Available Columns", startingSelection, addSelected).grid(column=1, row=0, sticky=(N,W))
class ColumnSelector(ttk.Frame):
def __init__(self, parent, labelText, startingSelection, function ):
listBox = Listbox(self, height=5, selectmode='multiple')
removeColumnsButton = ttk.Button(self, text="Move", command=function)
#(etc...)
答案 0 :(得分：2)
在实例中引用小部件的最佳方法是什么？ 其他课程？
我认为最常见的用例是重复使用一个对象无限次，因为看起来你正试图处理一些在框架内设置的列表框。在这种情况下，我认为您应该在子类中放置尽可能多的可重复代码，并在其中创建一个返回您想要的方法。在主类中创建子类的实例时，可以在需要时访问其方法（即selectedColumns.get_all_listbox_values()）。
您应该记住的一件事是，如果您创建实例并将其网格化在同一行上，该实例将无法正常工作：
否
selectedColumns = ColumnSelector(self, "Columns to include in export", (), removeSelected).grid(column=0, row=0, sticky=(N,W))
selectedColumns.get_all_listbox_values()
>>> AttributeError: 'NoneType' object has no attribute 'get_all_listbox_values'
是
selectedColumns = ColumnSelector(self, "Columns to include in export", (), removeSelected)
selectedColumns.grid(column=0, row=0, sticky=(N,W))
selectedColumns.get_all_listbox_values()
>>> (0, 1, 2, etc)
以下是设置脚本的一种方法示例。有一个主类（App）和另一个继承自Frame MyEntry）的类，可以多次在App中使用。 App类中有一个按钮打印出MyEntry中计算两个值的方法的结果。希望有助于为您提供有关构建代码的一些想法。
class App(Frame):
'''the main window class'''
def __init__(self, parent):
Frame.__init__(self, parent)
# create instances of MyEntry, passing whatever operators as args
# we can make as many of these instances as we need in just a couple of lines
# and it retains readability
self.divide = MyEntry(self, '/')
self.multiply = MyEntry(self, '*')
self.divide.pack()
self.multiply.pack()
Button(self, text='Calculate', command=self._print_result).pack()
def _print_result(self):
'''print the return of the calculate method from the instances of
the MyEntry class'''
print self.divide.calculate()
print self.multiply.calculate()
class MyEntry(Frame):
'''creates two entries and a label and has a method to calculate
the entries based on an operator'''
def __init__(self, parent, operator): # include the operator as an arg
Frame.__init__(self, parent)
# make an instance variable from the operator to access it between methods
self.operator = operator
# make two entries
self.num1 = Entry(self)
self.num2 = Entry(self)
# grid the entries and a label which contains the operator
self.num1.grid(row=0, column=0)
Label(self, text=self.operator).grid(row=0, column=1)
self.num2.grid(row=0, column=2)
def calculate(self):
'''return the value of the two entries based on the operator specified'''
if self.operator is '/':
return int(self.num1.get()) / int(self.num2.get())
elif self.operator is '*':
return int(self.num1.get()) * int(self.num2.get())
else:
return
root = Tk()
App(root).pack()
mainloop()