在 OptionMenu 选择更改后更新标签文本 [英] Updating Label text after OptionMenu selection changes

问题描述

我的目标是在每次选择选项菜单 w 中的新项目时更新标签 price 的内容.到目前为止，这是我的代码，但它返回了我不知道如何修复的错误.

My objective is to update the contents of the label price, every time that a new item in option menu w is selected. This is my code so far, but it is returning errors that I am not sure how to fix.

class App(Frame):

    def __init__(self, master=None):
        Frame.__init__(self, master)

        Label(master, text="Ore:").grid(row=0)
        Label(master, text="Price:").grid(row=1)
        self.price = Label(master, text="0.00").grid(row=1, column=1)

        variable = StringVar(master)
        variable.set("Select an ore") # default value

        def displayPrice(self):
            self.price = orePrice[self.w.get()]

        self.w = OptionMenu(master, variable, *orePrice, command=displayPrice).grid(row=0, column=1)

        # here is the application variable
        self.contents = StringVar()
        # set it to some value
        self.contents.set("this is a variable")
        # tell the entry widget to watch this variable
        #self.w.bind('<Button-1>', )

您可以假设:

orePrice = {'Gold': 300, 'Silver': 50, 'Bronze': 10} # etc... you can add more if you feel like it.

我是 Python GUI 的新手，因此代码凌乱和/或写得不好.

I'm a newbie at Python GUI, hence the messy and/or badly written code.

推荐答案

我修改了你的代码.现在，每当您更改矿石类型时，价格字段都会更新:

I ammended your code. Now whenever you change ore type, the price field is updated:

from tkinter import *


class App(Frame):
    def __init__(self, master=None):
        Frame.__init__(self, master)

        Label(master, text="Ore:").grid(row=0)
        Label(master, text="Price:").grid(row=1)

        self.priceVar = StringVar()
        self.priceVar.set("0.00")

        self.price = Label(master, textvariable=self.priceVar).grid(row=1, column=1)

        self.orePrice = {'Gold': 300, 'Silver': 50, 'Bronze': 10}

        variable = StringVar(master)
        variable.set("Select an ore") # default value


        self.w = OptionMenu(master, variable, *self.orePrice, command=self.displayPrice).grid(row=0, column=1)

        # here is the application variable
        self.contents = StringVar()
        # set it to some value
        self.contents.set("this is a variable")
        # tell the entry widget to watch this variable
        #self.w.bind('<Button-1>', )

    def displayPrice(self, value):
          self.priceVar.set(self.orePrice[value])


root = Tk()
app = App(root)
root.mainloop()  

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