Tkcalendar DateEntry - 允许小部件 Return 没有选择为空白

Question

我创建了一个 GUI，用户可以在其中 select 使用 tkcalendar DateEntry 小部件从下拉菜单中选择一个日期。我想允许用户选择不 select 日期并将此小部件留空。然而，即使没有日期 selected 小部件 returns 当前日期。

如果用户没有 select 日期，是否可以配置 DateEntry 以允许没有 selection 而不是默认为当前日期？

下面是我的代码的一个子集：

import pandas as pd
from tkinter import *
from tkinter.ttk import *
import tkinter as tk
from tkcalendar import DateEntry  

class Window(Frame):
    def __init__(self, master):
        Frame.__init__(self,master)
        master.title('Solar Master Project Tracking')

        # create canvas for scrollable window
        canvas = Canvas(root)
        canvas.grid(row=1,column=0, columnspan=2)

        # create vertical scrollbar and connect it to the canvas
        scrollBar = tk.Scrollbar(root, orient='vertical', command = canvas.yview)
        scrollBar.grid(row=1, column=2, sticky = 'ns')
        canvas.configure(yscrollcommand=scrollBar.set)

        def update_scroll_region(event):
            canvas.configure(scrollregion=canvas.bbox("all"))

        def _on_mousewheel(event):
            canvas.yview_scroll(int(-1*(event.delta/120)), "units")

        # create a frame for the widgets in the scrollable canvas
        scroll_frame = Frame(canvas)
        scroll_frame.bind("<Configure>", update_scroll_region)
        canvas.create_window(0,0, anchor='nw', window = scroll_frame)
        canvas.bind_all("<MouseWheel>", _on_mousewheel)

        # Proposal Date
        self.L18 = Label(scroll_frame, text="Proposal Date:",font=('TKDefaultFont', 8, 'bold'))
        self.L18.grid(row=21, column=0, sticky=W)
        self.prop_date_selection = DateEntry(scroll_frame, width = 25, background = 'LightCyan3',
                                             foreground ='white',borderwidth=2)
        self.prop_date_selection.grid(row=21, column=1,sticky=E)
        self.prop_date_selection.delete(0,"end")


        # SUBMIT INFORMATION
        self.button = tk.Button(root, text="Insert / Update Project",font=('TKDefaultFont', 10, 'bold'),
                                relief=RAISED, command = self.store_user_inputs, bg = "gray80")
        self.button.grid(row=25, column = 0, columnspan=8, sticky = 'EW')

    # STORE USER INPUT
    def store_user_inputs(self):
        prop_date_selection = self.prop_date_selection.get_date()

        global params
        params = [prop_date_selection]
        root.destroy()

if __name__ == "__main__":
    root = Tk()
    Window(root)
    root.mainloop()

Answer 1

可以创建一个继承自tkcalendar.DateEntry的class，当DateEntry为空时，将get_date()方法修改为return None：

import tkcalendar

class DateEntry(tkcalendar.DateEntry):
    def get_date(self):
        if not self.get():
            return None
        self._validate_date()
        return self.parse_date(self.get())

Answer 2

对于找到此 post 的人。

修改 get_date() 对我来说没有任何改变。但以下确实如此：

class MyDateEntry(tkcalendar.DateEntry):
    def _validate_date(self):
        if not self.get():
            return True # IMPORTANT!!! Validation must return True/False otherwise it is turned off by tkinter engine
        
        return super()._validate_date()

Tkcalendar DateEntry - 允许小部件 Return 没有选择为空白

Tkcalendar DateEntry - Allow Widget to Return No Selection as Blank

python-3.x

tkinter

tkcalendar