Question

所以我一直在研究一个项目，最近我的检查按钮遇到了问题。每当我尝试variablenname.get()时，它就不会像int value has no attribute get()那样工作。我确实也使用了variablename = IntVar()，我想做的是使if语句依赖于checkbutton的值。

        var = IntVar()
        BTR = Tk()
        Discounts = Checkbutton(BTR, text="Discount (Students, Under 18s, 65+ and Disability Badge Holders)", font = ("times", 30), bg="#252538", fg = "#99FFFF", variable = var)
        Discounts.place(x=120, y=300)
        PriceTag=Label(BTR, text =("£", Cost), font = ("times", 50), fg = "White", bg = "#252538")
        PriceTag.place(x=1000, y= 450)
        val=Label(BTR, text = Tickets, font = ("times", 22), height = 5, width = 15, bg= "White")
        val.place(x=175, y=550)
        add=Button(BTR, text = "+", font = ("times", 22), height = 5, width = 10, bg = "#B266FF", command = lambda: UpdateAdd(val, BTR, PriceTag, BusTicketPrice, price, var))
        add.place(x=420, y=550)

    def UpdateAdd(val, BTR, PriceTag, BusTicketPrice, price, var):
      var = var.get()
      Tickets = Tickets + 1 
      val.destroy()
      val = Label(BTR, text = Tickets, font = ("times", 22), height = 5, width = 15, bg= "White")
      val.place(x=175, y=550)
      PriceTag.destroy()
      if price == "Peak" and var == 0 :
          BusTicketPrice=BusTicketPrice*1.25
      elif var == 1 and price == "Peak":
          BusTicketPrice=BusTicketPrice
      elif var == 1 and price == "Off-Peak":
          BusTicketPrice=BusTicketPrice*0.75
      elif price == "Off-Peak" and var == 0):
          BusTicketPrice=BusTicketPrice
      Cost = BusTicketPrice * Tickets
      Cost = round(Cost, 3)
      PriceTag=Label(BTR, text =("£", str(Cost), "0"), font = ("times", 50), fg = "White", bg = "#252538")
      PriceTag.place(x=1000, y= 450)

Answer 1

此代码存在一些问题。首先，在创建根窗口并使用Tk()调用启动Tcl解释器之前，不应尝试创建任何Tkinter对象，包括窗口小部件和IntVar。我很惊讶你的代码没有打印出像

这样的错误信息

AttributeError: 'NoneType' object has no attribute '_root'

因为您在var = IntVar()之前有BTR = Tk()。我没有尝试运行您发布的代码，因为它不是MCVE。

你的错误的主要原因是UpdateAdd在函数开头附近var = var.get()（从var获取整数值然后将整数对象绑定到名称为var}，但稍后又有var.get()，但由于现在var引用了整数对象，而不是IntVar，因此无法工作它最初是绑定的。

这是一个最小程序，它表明使用带有Checkbutton的IntVar可以按预期工作。

import tkinter as tk

BTR = tk.Tk()
var = tk.IntVar()

title = tk.Label(BTR, text="Purchase Bus or Tram Tickets")
title.pack()

discounts = tk.Checkbutton(BTR, text="Discount", variable=var)
discounts.pack()

test = tk.Button(BTR, text="test", command=lambda: print(var.get()))
test.pack()

BTR.mainloop()

按＆＃34;测试＆＃34;按钮，Checkbutton的当前状态将打印到控制台。

我不能使用.get（）获取我的Tkinter Checkbutton变量值

1 个答案: