更新时绑定到StringVar的Tkinter Label落后一键

The problem I'm running into here is that, when I click on the different file names in the Listbox, the Label changes value one click behind whatever I'm currently clicking on.

我在这里错过了什么?

import Tkinter as tk

class TkTest: 

    def __init__(self, master):

        self.fraMain = tk.Frame(master)
        self.fraMain.pack()

        # Set up a list box containing all the paths to choose from
        self.lstPaths = tk.Listbox(self.fraMain)
        paths = [
            '/path/file1',
            '/path/file2',
            '/path/file3',
        ]
        for path in paths:
            self.lstPaths.insert(tk.END, path)
        self.lstPaths.bind('<Button-1>', self.update_label)
        self.lstPaths.pack()

        self.currentpath = tk.StringVar()
        self.lblCurrentPath = tk.Label(self.fraMain, textvariable=self.currentpath)
        self.lblCurrentPath.pack()

    def update_label(self, event):
        print self.lstPaths.get(tk.ACTIVE),
        print self.lstPaths.curselection()
        self.currentpath.set(self.lstPaths.get(tk.ACTIVE))

root = tk.Tk()
app = TkTest(root)
root.mainloop()

解决方案

问题与 Tk 的基本设计有关.简短的版本是，特定小部件上的绑定在小部件的默认类绑定之前触发.它是在类绑定中更改列表框的选择.这正是您所观察到的——您看到的是当前点击之前的选择.