使用 for 循环从 tkinter 复选框创建和获取值

Question

此代码是我项目的一部分，我必须管理 50 名（或更多）学生的出勤率。

我想要的是所有复选框最初都应该被“选中”（显示当前状态），当我取消选中随机复选框时（标记缺席）并单击Submit 按钮（尚未在窗口底部创建），我应该得到一个列表，其中“输入日期”作为第一个元素和卷号，即 2018-MC-XX和其他元素一样。

例如： ['01/08/2020', '2018-MC-7', '2018-MC-11', '2018-MC-23', '2018-MC-44']

实际上我的计划是当我得到一个列表时，我会很容易地将它写入一个文本文件。另外，如果有另一种方法可以创建多个可滚动复选框而不将它们打包在画布中，那么请告诉！

from tkinter import *
from tkcalendar import DateEntry

root = Tk()
root.geometry('920x600+270+50')
root.minsize(920,600)

Attendance_frame = Frame(root)    ### Consider it a Main Frame
Attendance_frame.pack()

attendaceBox = LabelFrame(Attendance_frame, text = 'Take Attendance', bd = 4, relief = GROOVE, labelanchor = 'n',font = 'Arial 10 bold', fg = 'navy blue', width = 850, height = 525)     # A Label Frame inside the main frame

attendaceBox.pack_propagate(0)
attendaceBox.pack(pady = 15)

dateFrame = Frame(attendaceBox)    # A small frame to accommodate date entry label & entry box
dateFrame.pack(anchor = 'w')

font = 'TkDefaultFont 10 bold'
date_label = Label(dateFrame, text = 'Enter Date : ', font = font).grid(row = 0, column =  0, sticky = 'w', padx = 10, pady = 10)

date_entry = DateEntry(dateFrame, date_pattern = 'dd/mm/yyyy', showweeknumbers = FALSE, showothermonthdays = FALSE)
date_entry.grid(row = 0, column = 1, sticky = 'w')

noteLabel = Label(attendaceBox, text = 'Note: Uncheck the boxes for absentees').pack(anchor = 'w', padx = 10, pady = 5)

canvas = Canvas(attendaceBox, borderwidth=0, background="#ffffff")
checkFrame = Frame(canvas, width = 100, height = 50)
vsb = Scrollbar(canvas, orient="vertical", command=canvas.yview)
canvas.configure(yscrollcommand=vsb.set)

vsb.pack(side="right", fill="y")
canvas.pack(side="left", fill="both", expand=True)
canvas.pack_propagate(0)
canvas.create_window((4,4), window=checkFrame, anchor="nw")

def onFrameConfigure(canvas):
    '''Reset the scroll region to encompass the inner frame'''
    canvas.configure(scrollregion=canvas.bbox("all"))

checkFrame.bind("<Configure>", lambda event, canvas=canvas: onFrameConfigure(canvas))

for i in range(0,51):     # A loop to create Labels of students roll numbers & names
    c = Checkbutton(checkFrame, text = f"{'2018-MC-'+str(i+1)}       Student {i+1}")
    c.grid(row = i, column = 0, padx = 10, sticky = 'w')


mainloop()

Answer 1

首先，您需要为每个 Checkbutton 提供StringVar，以便稍后获取Checkbuttons 的状态。然后您可以使用列表来保存StringVars，以便您以后可以访问它们。您可以将checkbuttons 的onvalue 设置为与它们关联的卷号。

您也可以使用Text 小部件代替Canvas+Frame。下面是一个例子：

import tkinter as tk

root = tk.Tk()

frame = tk.Frame(root)
frame.pack()

text = tk.Text(frame, width=40, height=20)
text.pack(side=tk.LEFT, fill=tk.BOTH)

vars = []
for i in range(51):
    rollnum = '2018-MC-'+str(i+1)
    var = tk.StringVar(value=rollnum)
    cb = tk.Checkbutton(text, text=rollnum, variable=var, onvalue=rollnum, offvalue='', bg='white')
    text.window_create('end', window=cb)
    text.insert('end', '\n')
    vars.append(var)

vsb = tk.Scrollbar(frame, orient=tk.VERTICAL, command=text.yview)
vsb.pack(side=tk.RIGHT, fill=tk.Y)

text.config(yscrollcommand=vsb.set)

def submit():
    # extract roll numbers for checked checkbuttons
    result = [var.get() for var in vars if var.get()]
    print(result)

tk.Button(root, text='Submit', command=submit).pack()

root.mainloop()