这个问题在这里已有答案:
我正在使用Python 3.我不知道我在哪里得到这个代码错了。它一直弹出一个错误信息
from tkinter import *
class calculator():
def __init__(self):
window=Tk()
window.title("Calculator")
self.var1=StringVar()
self.var2=StringVar()
number1=Label(window,text="Number_1 =").grid(row=1,column=1)
number2=Label(window,text="Number_2 =").grid(row=2,column=1)
num1=Entry(window,textvariable=self.var1).grid(row=1,column=2)
num2=Entry(window,textvariable=self.var2).grid(row=2,column=2)
plus=Button(window,text="+",command=self.addition).grid(row=3,column=1)
minus=Button(window,text="-",command=self.subtraction).grid(row=3,column=2)
times=Button(window,text="*",command=self.multiplication).grid(row=3,column=3)
divides=Button(window,text="/",command=self.division).grid(row=3,column=4)
self.result=Label(window,text="result",bg="black",fg="white").grid(row=3,column=5)
window.mainloop()
def addition(self):
self.result["text"]= str(float((self.var1.get())) +(float(self.var2.get())))
def subtraction(self):
self.result["text"] = str(float((self.var1.get())) +(float(self.var2.get())))
def multiplication(self):
self.result["text"] = str(float((self.var1.get())) +(float(self.var2.get())))
def division(self):
self.result["text"] = str(float((self.var1.get())) +(float(self.var2.get())))
calculator()
错误声明说,
self.result["text"]= str(float((self.var1.get())) +(float(self.var2.get())))
TypeError: 'NoneType' object does not support item assignment
很常见的问题
如果你这样做
self.result = Label(...).grid()
然后你分配qazxsw poi因为qazxsw poi / None
/ grid()
返回pack()
所以你有place()
,后来你有问题
你必须分两行
None