如何通过输入框将多个值从一个函数返回到另一个函数？（ValueError：无法将字符串转换为浮点：）

Question

我对tkinter和python确实是个新手，我尝试使用tkinter创建GUI。这个示例只是计算两个数的乘法和加法并返回，当我不能将字符串转换为输入时（这意味着没有输入），我只能生成结果。那么，我如何将这2个值返回给另一个函数呢？

import tkinter as tk

'''OS'''
root = tk.Tk()
root.title("Simple Box")
operator=""

canvas = tk.Canvas(root, height=400,width=500,bg="White")
canvas.pack()

frame=tk.Frame(root, bg="Light Blue")
frame.place(relwidth=0.9,relheight=0.9, relx=0.05, rely=0.05)
'''Variable '''
num1= tk.StringVar()
num2= tk.StringVar()

''' function'''
def operation1():
    global number1, number2
    multi_add =tk.Tk()
    multi_add.title("Multiplication and Addition")

    tk.Label(multi_add, font =("Helvetica", 20),
             text="Enter the first number:").grid(row=0)
    tk.Label(multi_add, font =("Helvetica", 20),
             text="Enter the second number").grid(row=1)

    number1=tk.Entry(multi_add, textvariable = num1).grid(row=0, column=1)
    number2=tk.Entry(multi_add, textvariable = num2).grid(row=1, column=1)

    return num1, num2 


def result():
    num3 = float(num1.get()) + float(num2.get())
    num4 = float(num1.get()) * float(num2.get())
    print("the result is ",num3 ,"and", num4)

'''buttons'''
result=tk.Button(frame, text="Result", font=('airal', 30 ,'bold'), height="1"
                 ,width="6", padx=10,pady=5, fg="Black",
                 bg="yellow", command= result)
result.place(x=300 , y=305)

op1=tk.Button(frame, text="operation 1", height="2", width="10", padx=10,
             pady=5, fg="Black", bg="yellow", command = operation1)
op1.place(x = 17, y = 310)


root.mainloop()

TracebackError：

D Tkinter回调中的异常：Traceback（最近一次调用）：文件“/library/framework/python.framework/versions/3.7/lib/python3.7/Tkinter/init.py”，第1705行，在call return self.func(*args)文件“/users/pozzphut/desktop/project python/figurefunction transfer.py”，第37行，在结果num3=float(num1.get())+float(num2.get())中值错误：无法将字符串转换为float：

Answer 1

以下是解决方案：

如果在同一行中使用.grid()，则number1和number2将返回none并且我们无法获取数据。

修改如下：

    number1=tk.Entry(multi_add, textvariable = num1)
    number2=tk.Entry(multi_add, textvariable = num2)
    number1.grid(row=0, column=1)
    number2.grid(row=1, column=1)

def result():
    num3 = float(number1.get()) + float(number2.get())
    num4 = float(number1.get()) * float(number2.get())

import tkinter as tk

'''OS'''
root = tk.Tk()
root.title("Simple Box")
operator=""

canvas = tk.Canvas(root, height=400,width=500,bg="White")
canvas.pack()

frame=tk.Frame(root, bg="Light Blue")
frame.place(relwidth=0.9,relheight=0.9, relx=0.05, rely=0.05)
'''Variable '''
num1= tk.StringVar()
num2= tk.StringVar()

''' function'''
def operation1():
    global number1, number2
    multi_add =tk.Tk()
    multi_add.title("Multiplication and Addition")

    tk.Label(multi_add, font =("Helvetica", 20),
             text="Enter the first number:").grid(row=0)
    tk.Label(multi_add, font =("Helvetica", 20),
             text="Enter the second number").grid(row=1)

    number1=tk.Entry(multi_add, textvariable = num1)
    number2=tk.Entry(multi_add, textvariable = num2)
    number1.grid(row=0, column=1)
    number2.grid(row=1, column=1)

def result():
    num3 = float(number1.get()) + float(number2.get())
    num4 = float(number1.get()) * float(number2.get())
    print("the result is ",num3 ,"and", num4)

'''buttons'''
result=tk.Button(frame, text="Result", font=('airal', 30 ,'bold'), height="1"
                 ,width="6", padx=10,pady=5, fg="Black",
                 bg="yellow", command= result)
result.place(x=300 , y=305)

op1=tk.Button(frame, text="operation 1", height="2", width="10", padx=10,
             pady=5, fg="Black", bg="yellow", command = operation1)
op1.place(x = 17, y = 310)


root.mainloop()

import tkinter as tk

'''OS'''
root = tk.Tk()
root.title("Simple Box")
operator=""

canvas = tk.Canvas(root, height=400,width=500,bg="White")
canvas.pack()

frame=tk.Frame(root, bg="Light Blue")
frame.place(relwidth=0.9,relheight=0.9, relx=0.05, rely=0.05)

''' function'''
def operation1():
    global number1, number2
    multi_add =tk.Tk()
    multi_add.title("Multiplication and Addition")

    tk.Label(multi_add, font =("Helvetica", 20),
             text="Enter the first number:").grid(row=0)
    tk.Label(multi_add, font =("Helvetica", 20),
             text="Enter the second number").grid(row=1)

    number1=tk.Entry(multi_add)
    number2=tk.Entry(multi_add)
    number1.grid(row=0, column=1)
    number2.grid(row=1, column=1)

def result():
    num3 = float(number1.get()) + float(number2.get())
    num4 = float(number1.get()) * float(number2.get())
    print("the result is ",num3 ,"and", num4)

'''buttons'''
result=tk.Button(frame, text="Result", font=('airal', 30 ,'bold'), height="1"
                 ,width="6", padx=10,pady=5, fg="Black",
                 bg="yellow", command= result)
result.place(x=300 , y=305)

op1=tk.Button(frame, text="operation 1", height="2", width="10", padx=10,
             pady=5, fg="Black", bg="yellow", command = operation1)
op1.place(x = 17, y = 310)


root.mainloop()