entry.get() 函数不会改变变量的值

Question

我有一些代码要求用户输入他们想要加密的单词，然后程序将加密该单词并将其显示在标签上。我想知道为什么以下代码有效：

import tkinter

letters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'

encryption_code = 'LFWOAYUISVKMNXPBDCRJTQEGHZ'
letters += letters.lower()
encryption_code += encryption_code.lower()

window = tkinter.Tk()
encryption_code_entry = tkinter.Entry(window)
entry = tkinter.Entry(window)

enc = dict(zip(letters,encryption_code))

string = 'hello world'

encr = "".join([enc.get(ch, ch) for ch in string])

def encrypt():    
    encrypt_label.pack()
    entry.pack()
    encrypt_confirm.pack()
    encrypt_button.destroy()

def display_encrypt():
    display_enc = encr
    encrypted_label.pack()
    new_message.config(text=str(display_enc))
    new_message.pack()

encrypt_confirm = tkinter.Button(window, text="Confirm", command=display_encrypt)
new_message = tkinter.Label(window, text="", font=('Helvetica', 10))
encrypted_label = tkinter.Label(window, text="Your message " + entry.get() + " has been encrypted into the following: ")
encrypt_button = tkinter.Button(window, text="Encrypt", command=encrypt)
encrypt_button.pack()
encrypt_label = tkinter.Label(window, text="Please enter the message you'd like to encrypt", font=('Helvetica', 14))

window.mainloop()

但是如果我将 string = 'hello world'（这是我想做的）更改为 string = entry.get()，则不会显示任何内容onnew_message`。另外，

encrypted_label = tkinter.Label(window, text="Your message " + entry.get() + "has been encrypted into the following: ")

不显示用户在输入框中输入的内容，所以我几乎 100% 确定我滥用了 entry.get() 函数。

Answer 1

您在用户有机会输入任何内容之前调用 entry.get()。您需要调用它并重置标签以响应事件，例如用户按下、单击按钮等。

Answer 2

您实际上需要 entry.get() 在 display_encrypt() 下。

每次按下 encrypt_confirm 按钮时，它都会调用 display_encrypt，然后每次用户按下它时，它又能够在 entry 中获取当前字符串.

我稍微编辑了您的代码，它似乎可以正常工作。

请注意，我已经删除了 string 和 encr，因为它们现在是冗余变量。

import tkinter

letters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'

encryption_code = 'LFWOAYUISVKMNXPBDCRJTQEGHZ'
letters += letters.lower()
encryption_code += encryption_code.lower()

window = tkinter.Tk()
encryption_code_entry = tkinter.Entry(window)
entry = tkinter.Entry(window)

enc = dict(zip(letters,encryption_code))

string = 'hello world'

def encrypt():    
    encrypt_label.pack()
    entry.pack()
    encrypt_confirm.pack()
    encrypt_button.destroy()

def display_encrypt():
    display_enc = "".join([enc.get(ch, ch) for ch in entry.get()])
    encrypted_label.pack()
    new_message.config(text=str(display_enc))
    new_message.pack()

encrypt_confirm = tkinter.Button(window, text="Confirm", command=display_encrypt)
new_message = tkinter.Label(window, text="", font=('Helvetica', 10))
encrypted_label = tkinter.Label(window, text="Your message " + entry.get() + " has been encrypted into the following: ")
encrypt_button = tkinter.Button(window, text="Encrypt", command=encrypt)
encrypt_button.pack()
encrypt_label = tkinter.Label(window, text="Please enter the message you'd like to encrypt", font=('Helvetica', 14))

window.mainloop()

entry.get() 函数不会改变变量的值

entry.get() function won't change value of a variable

python

label

tkinter

function