Tkinter - 当框架内的标签数量发生变化时，滚动条不会调整大小

Question

我正在尝试创建一个 GUI，其中左侧是 Listbox（包含在框架 f2 内），显示员工 ID，右侧是另一个框架 second_frame（包含在画布内和外框架 @987654324 @)，以标签的形式显示每个选定员工的交易详情。

每个员工可以进行多项交易。因此，标签的数量必须是动态的，即对于listbox 中的第一个选定项目，可能有两个标签，而对于listbox 中的第二个选定项目，它可能是一百个。对于每个选择，我调用两个函数来销毁旧标签和创建新标签。虽然代码工作正常，但我无法根据选定的 listbox 条目调整滚动条的大小。我是 Tkinter 的新手，请指教。下面是我的代码。

另请注意，从任何函数外部调用 test() 函数时会显示滚动条，但从任何函数内部调用时不会显示任何内容。

# -*- coding: utf-8 -*-
from tkinter import *

'''def test():
    for i in range(0,50):
        for j in range (0,7):
            Label(second_frame, text=f'{i}{j}', width=20).grid(row=i, column=j, pady=5,padx=5)
'''
# --- function ---
def destroy_frame():
    #f1.grid_forget()
    print("destroying frame")
    for label in second_frame.winfo_children():
        label.destroy()

def create_frame(val):
    print("creating new frame")
    for i in range(0,val):
        for j in range (5):
            Label(second_frame, text=f'{i} {j} ', relief=GROOVE, width=10).grid(row=i, column=j, pady=5,padx=5)

def on_selection(event):
    # here you can get selected element
    print('previous:', listbox.get('active'))
    print(' current:', listbox.get(listbox.curselection()))

    # or using `event`
    print('(event) previous:', event.widget.get('active'))
    print('(event)  current:', event.widget.get(event.widget.curselection()))

    print (listbox.get(listbox.curselection()))

    if (listbox.get(listbox.curselection()) == "Eid 1"):
        destroy_frame()
        create_frame(100)

    elif (listbox.get(listbox.curselection()) == "Eid 2"):
        destroy_frame()
        create_frame(200)

    print('---')


root = Tk()
root.geometry('800x500')

#Create base Frames
f1 = Frame(width=800, height=50, bg="yellow", colormap="new")
f1.grid(row=0, columnspan=2)
f1.grid_propagate(False)

f2 = Frame(width=200, height=425, bg="light blue", colormap="new")
f2.grid(row=1, column=0)
f2.grid_propagate(False)

f3 = Frame(width=600, height=425, bg="light green", colormap="new")
f3.grid(row=1, column=1)
f3.grid_propagate(False)

#Create header Label
l1_f1 = Label(f1, text="Employee Purchase Entries:", bg="yellow")
l1_f1.grid(row=0, column=0)

#Create Listbox
listbox = Listbox(f2, bg="light blue", width=40, height=400)
listbox.grid(row=0, column=0)

#Add Scrollbar to ListBox
list_scrollbar = Scrollbar(f2)
list_scrollbar.grid(row=0, column=1, sticky=NSEW)

#Enter Listbox Data
listbox.insert(1, 'Eid 1')
listbox.insert(2, 'Eid 2')

listbox.bind('<<ListboxSelect>>', on_selection)

#configure the Listbox and Scrollbar
listbox.config(yscrollcommand  = list_scrollbar.set)
list_scrollbar.config(command = listbox.yview)

#Create a Canvas
my_canvas = Canvas(f3, width=580, height=425, bg="light green")
#my_canvas.pack(side=LEFT, fill=BOTH, expand=1)
my_canvas.grid(row=0, column=0)

#Add a Scrollbar to the canvas
my_scrollbar = Scrollbar(f3, orient=VERTICAL, command=my_canvas.yview)
my_scrollbar.grid(row=0, column=1, sticky=NSEW)

#configure the canvas
my_canvas.configure(yscrollcommand=my_scrollbar.set)
my_canvas.bind('<Configure>', lambda e : my_canvas.configure(scrollregion = my_canvas.bbox("all")))

#Create another frame inside the canvas
second_frame = Frame(my_canvas)

#Add the new frame to a window in the canvas
my_canvas.create_window((0,0), window=second_frame, anchor="nw")


#test()

root.mainloop()

Answer 1

当您将小部件添加到框架时，您的画布不会触发配置事件。相反，您的框架已被触发。

所以你需要把这一行：

second_frame.bind('<Configure>', lambda e : my_canvas.configure(scrollregion = my_canvas.bbox("all")))

创建second_frame之后