当 Tkinter 列表框选择更改时获得回调? [英] Getting a callback when a Tkinter Listbox selection is changed?

问题描述

在 Tkinter 中更改 Text 或 Entry 小部件时，有多种获取回调的方法，但我还没有找到用于 Listbox's(它没有帮助我能找到的大部分事件文档是旧的或不完整的).有没有办法为此生成事件?

There are a number of ways of getting callbacks when Text or Entry widgets are changed in Tkinter, but I haven't found one for Listbox's (it doesn't help that much of the event documentation I can find is old or incomplete). Is there some way of generating an event for this?

推荐答案

您可以绑定到 <<> 事件.在选择变化时，将生成此事件，无论它是否从按钮，通过键盘或任何其他方法都会从按钮中更改.

You can bind to the <<ListboxSelect>> event. This event will be generated whenever the selection changes, whether it changes from a button click, via the keyboard, or any other method.

这里有一个简单的例子，当你从列表框中选择一些东西时，它会更新一个标签:

Here's a simple example which updates a label whenever you select something from the listbox:

import tkinter as tk

root = tk.Tk()
label = tk.Label(root)
listbox = tk.Listbox(root)
label.pack(side="bottom", fill="x")
listbox.pack(side="top", fill="both", expand=True)

listbox.insert("end", "one", "two", "three", "four", "five")

def callback(event):
    selection = event.widget.curselection()
    if selection:
        index = selection[0]
        data = event.widget.get(index)
        label.configure(text=data)
    else:
        label.configure(text="")

listbox.bind("<<ListboxSelect>>", callback)

root.mainloop()

此事件在规范的列表框手册页中提及.所有预定义的虚拟事件都可以在 绑定手册页.

This event is mentioned in the canonical man page for listbox. All predefined virtual events can be found on the bind man page.

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