python - "TypeError: Can' t 将 'NoneType' 对象隐式转换为 str"当 var 应该有一个值时

Question

import sys
from tkinter import *
def print():
    print("Encoded " + message + " with " + offset)

gui = Tk()

gui.title("Caesar Cypher Encoder")

Button(gui, text="Encode", command=encode).grid(row = 2, column = 2)
Label(gui, text = "Message").grid(row = 1, column =0)
Label(gui, text = "Offset").grid(row = 1, column =1)
message = Entry(gui).grid(row=2, column=0)
offset = Scale(gui, from_=0, to=25).grid(row=2, column=1)

mainloop( )

当我在输入框中输入一个输入并在 slider 上输入一个值来运行此代码时 - 它会出现错误

>>>Exception in Tkinter callback
Traceback (most recent call last):
File "C:\Python34\lib\tkinter\__init__.py", line 1533, in __call__
return self.func(*args)
File "C:/Users/xxxx/Desktop/Code/Functionised/GUI.pyw", line 5, in encode
print("Encoded " + message + " with " + offset)
TypeError: Can't convert 'NoneType' object to str implicitly

使用简单的 str() 方法是行不通的

编辑

使用新代码

import sys
from tkinter import *
def printer():
    print(message)
    print(offset)

gui = Tk()

gui.title("Caesar Cypher Encoder")

Button(gui, text="Encode", command=printer).grid(row = 2, column = 2)
Label(gui, text = "Message").grid(row = 1, column =0)
Label(gui, text = "Offset").grid(row = 1, column =1)
message = Entry(gui)
message.grid(row=2, column=0)
offset = Scale(gui, from_=0, to=25)
offset.grid(row=2, column=1)

mainloop( )

返回

.46329264
.46329296

编辑2

def printer():
    print(message.get())
    print(offset.get())

这解决了 .xxxxxxxx 问题

Answer 1

回答您的第一次编辑 - .get() 命令应该是最有用的

以

的形式使用

print(message.get())

而不是

print(message)