Python - Tkinter - 来自 StringVar 的标签文本不 display/update

Question

我正在尝试将我之前编写的简单命令行程序转换为具有 GUI。在开始向我的 existing/working 代码添加内容之前，我想尝试一下在 Tkinter 中构建 GUI。我终于开始取得进展，让事情按照我想要的方式显示，直到我得到我想让它们的显示文本根据变量的内容而改变的小部件。

根据我在此处和各种文档集中阅读的内容，执行此操作的方法是使用 StringVar，我曾尝试这样做，但是当我运行程序，status_msg 标签小部件的文本根本不显示。我尝试在几个地方调用 set() 来更新变量，虽然它似乎更新了变量，但标签根本没有出现在 window 中。最后我尝试添加一个 "Add Key" 按钮调用的函数来强制调用 set 并尝试显示标签，但它仍然不起作用，尽管它确实打印出我对控制台的期望。

我不知道我做错了什么。这是我的代码：

import tkinter as tk

numkeys = 0
keystring = str(numkeys) + " entries ready for parsing"
class Application(tk.Frame):
    def __init__(self, master=None):
        tk.Frame.__init__(self, master)
        self.grid()
        self.createWidgets()

    def createWidgets(self):
        self.numkeys = tk.StringVar()
        self.numkeys.set(keystring)

        api_frame = tk.LabelFrame(self, text="Key Entry", padx = 5, pady = 5)
        api_frame.grid(padx = 10, pady = 10)
        key1_lbl = tk.Label(api_frame, text = "Entry 1:", anchor = tk.W)
        key1_lbl.grid(row = 0, column = 0)
        self.key = tk.Entry(api_frame, width = 18)
        self.key.grid(row = 0, column = 1)
        key2_lbl = tk.Label(api_frame, text="Entry 2:")
        key2_lbl.grid(row = 0, column = 2, padx = 5)
        self.key2 = tk.Entry(api_frame, width = 45)
        self.key2.grid(row = 0, column = 3, padx = 2, columnspan = 3)
        status_msg = tk.Label(api_frame, textvariable = self.numkeys.get())
        status_msg.grid(row = 1, column = 0, columnspan = 3)
        btn_submit = tk.Button(api_frame, text="Add Key", width = 12, command = self.test)
        btn_submit.grid(row = 1, column = 4, pady = 5)
        btn_start = tk.Button(api_frame, text="Parse Keys", width = 12, command = None)
        btn_start.grid(row = 1, column = 5, pady = 5)

        #self.numkeys.set(keystring)

    def test(self):
        self.numkeys.set(keystring)
        root.update_idletasks()
        print("test function ran")
        print(app.numkeys.get())

root = tk.Tk()
app = Application(master=root)
app.master.title('Tk test')
app.mainloop()

Answer 1

替换

textvariable = self.numkeys.get()

来自

textvariable = self.numkeys

Python - Tkinter - 来自 StringVar 的标签文本不 display/update

Python - Tkinter - Label text from StringVar does not display/update

tkinter

python-3.x