Question

我已经读过Why is Button parameter “command” executed when declared?，而Bryan Oakley提供的解决方案看起来很有用，但是就我而言，我需要一些不同的东西（或者我错了）。因为我需要在类MainFrame中传递参数。

我的代码：

views / login.py

import tkinter as tk

from AgileBooks.controllers.login import submit_login

global_font = 'Helvetica'
global_bg = 'gray25'
global_fg = 'lawn green'


class MainFrame():
    # Frame:
    frm_login = tk.Tk()
    frm_login.title('Login | AgileBooks - Copyright Gonzalo Dambra')
    frm_login.geometry('400x300')
    frm_login.configure(background=global_bg)
    # Labels:
    lbl_username = tk.Label(frm_login, text='Username', bg=global_bg, fg=global_fg, font=(global_font, 16))
    lbl_username.place(x=150, y=50)
    lbl_password = tk.Label(frm_login, text='Password', bg=global_bg, fg=global_fg, font=(global_font, 16))
    lbl_password.place(x=150, y=125)
    # Inputtexts:
    txt_username = tk.Entry(frm_login, font=(global_font, 14))
    txt_username.focus()
    txt_username.place(x=100, y=80, height=25, width=200)
    txt_password = tk.Entry(frm_login, show='*',font=(global_font, 14))
    txt_password.place(x=100, y=155, height=25, width=200)
    # Button:
    btn_login = tk.Button(frm_login, text='Login', font=(global_font, 16), bg=global_bg, fg=global_fg,
                          command=submit_login(txt_username.get(), txt_password.get()))
    btn_login.place(x=165, y=200, height=25)


def main():
    frame = MainFrame()
    frame.frm_login.mainloop()


if __name__ == '__main__':
    main()

controllers / login.py：

def submit_login(username, password):
    if len(username) > 0 and len(password) > 0:
        print('Username: ', username, ' | Password: ', password)
    else:
        print('One of the fields is not filled.')

我的问题是方法submit_login的调用没有任何单击事件，只是在代码运行时才调用它。我在做什么错了？

Answer 1

将submit_login绑定到按钮时，您正在呼叫它：

command=submit_login(txt_username.get(), txt_password.get())

相反，您可以在Tkinter中将命令绑定到lambda：

command=lambda username=txt_username.get(), password=txt_password.get(): submit_login(username, password)

您可能还希望将呼叫移至.get()，以便在单击时发生：

btn_login = tk.Button(frm_login, text='Login', font=(global_font, 16), bg=global_bg, fg=global_fg,    
                      command=lambda username=txt_username, password=txt_password: submit_login(username, password)


def submit_login(username, password):
    username = username.get()
    password = password.get()
    if len(username) > 0 and len(password) > 0:
        print('Username: ', username, ' | Password: ', password)
    else:
        print('One of the fields is not filled.')

Python：任何单击之前都会调用Button的命令事件

1 个答案: