使用 for 循环从 tkinter 复选框创建和获取值

Question

此代码是我的项目的一部分，我必须在该项目中管理 50 名（或更多）学生的出勤率。

我想要的是所有复选框最初应该是 'checked' （显示当前状态） 当我取消选中随机复选框时 (标记不存在)然后点击Submit按钮(yet to be created at the bottom of the window),我应该得到一个以 'entered date' 作为第一个元素并以卷号（即 2018-MC-XX）作为其他元素的列表。

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 canvas 中，那么请告诉我！

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，每个 Checkbutton 都需要 StringVar，以便稍后获取 Checkbuttons 的状态。然后你可以使用一个列表来保存 StringVars 以便你以后可以访问它们。您可以将 checkbuttons 的 onvalue 设置为与其关联的卷号。

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()

使用 for 循环从 tkinter 复选框创建和获取值

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