如何通过Tkinter中的按钮传递参数

Question

我正在尝试为学校项目使用Python 3.7创建一个基本程序，该项目在按下按钮时会打印一串文本。 有人对我做错了什么有什么想法吗？

我尝试使用lambda函数，但它给了我一条错误消息。

#This is what I have tried:

import tkinter

window = tkinter.Tk()
button1 = tkinter.Button(window, text = "Press Me1", command= lambda: action("1"))
button2 = tkinter.Button(window, text = "Press Me2", command= lambda: action("2"))
button1.pack()
button2.pack()
window.mainloop()

if button1 == "1":
    print("Button 1 was pressed.")
elif button2 == "2":
    print("Button 2 was pressed.")

I'm expecting that, when you press one of the buttons, it prints the specified statement.

#However, I get the following error message:

Exception in Tkinter callback
Traceback (most recent call last):
    File "C:\Users\liamd\AppData\Local\Programs\Python\Python37-32\lib\tkinter\__init__.py", line 1705, in __call__
    return self.func(*args)
    File "C:\Users\liamd\Documents\!!!!MY STUFF!!!!\Python\Bankaccount Assessment - Simplified - And Again.py", line 4, in <lambda>
    button1 = tkinter.Button(window, text = "Press Me1", command= lambda: action("1"))
NameError: name 'action' is not defined

Answer 1

您需要在调用action函数之前为其提供一个实现，例如：

def action(message):
    print(message)

因此，您的代码如下所示：

import tkinter

def action(message):
    print(message)

window = tkinter.Tk()
button1 = tkinter.Button(window, text = "Press Me1", command= lambda: action("Button 1 was pressed"))
button2 = tkinter.Button(window, text = "Press Me2", command= lambda: action("Button 2 was pressed"))
button1.pack()
button2.pack()
window.mainloop()

或者，您也可以将所有action调用替换为print()调用：

button1 = tkinter.Button(window, text = "Press Me1", command= lambda: print("Button 1 was pressed"))
button1 = tkinter.Button(window, text = "Press Me1", command= lambda: print("Button 2 was pressed"))

if条件不会执行任何操作，因为它们不是由按下按钮触发的。

Answer 2

这样做的另一种方法是为按下按钮定义特定的功能。 如果您打算在按钮按下时发生其他事情，那么这可能会有所帮助。

import tkinter

#This is what I added to get the buttons to work.
def on_button_1():
    print('Button 1 was pressed.')
def on_button_2():
    print('Button 2 was pressed.')


window = tkinter.Tk()
#changed these next 2 lines so that each button calls the appropriate function
button1 = tkinter.Button(window, text = "Press Me1", command= on_button_1)
button2 = tkinter.Button(window, text = "Press Me2", command= on_button_2)
button1.pack()
button2.pack()
window.mainloop()