替换 tkinter 列表框中的预定义键绑定函数 [英] Replace predefined key binded functions in tkinter Listbox

问题描述

我创建了一个列表框，我希望 Left 和 Right 箭头键(分别)上下移动列表框，但是→和←键的默认键绑定功能是像水平滚动一样左右移动列表.

I've created a listbox and I want the Left and Right arrow keys to move up and down the listbox (respectively) but the default key binded functions of → and ← keys are to move the list left and right like a horizontal scroll.

如何替换左右键的功能?

How do I replace the function of the left and right keys?

代码看起来像这样:

from tkinter import *                                                
window=Tk()                                                          
list_b=Listbox()                                                     
                                                                     
list_b.insert(END,'line 1')                                          
list_b.insert(END,'line 2')                                          
list_b.insert(END,'this is a really really really long line')        
list_b.insert(END,'line 4')                                          
                                                                     
list_b.grid()

list_b.disable_horizontal_scroll() #some method to disable horizontal scroll                                                           
list_b.bind('<Right>',move_down) # has the same effect as the up arrow key                                    
list_b.bind('<Left>',move_up)    # has the same effect as the down arrow key                                  
list_b.focus()                                                       
                                                                     
                                                                     
window.mainloop()

我已经从 如何在 Tkinter 列表框中禁用水平滚动?(Python 3) 但它不会禁用水平滚动.

I've already tried list_b.bind("<B1-Leave>", lambda event: "break") from How can I disable horizontal scrolling in a Tkinter listbox? (Python 3) but it does not disable horizontal scrolling.

注意-

我不是要替换 ↑ 和 ↓ 键，我问了这个问题，因为它是更大、更复杂代码和给定代码段的一部分代码只是一个例子.

I'm not trying to replace the ↑ and ↓ keys, I asked this question as it is a segment of a larger, more complex code and the given snippet of the code is merely an example.

推荐答案

您所要做的就是在函数的末尾return 'break'.由于我不知道您的功能，因此我为此目的制作了自己的功能，例如:

All you have to do is return 'break' at the end of your function. Since I dont know your functions, I made my own for this purpose, like:

def move_down():
    try:
        idx = list_b.curselection()[0]
        list_b.selection_clear(0,'end')
        list_b.selection_set(idx+1)
        list_b.activate(idx+1)
        return 'break'
    except IndexError:
        idx = 0
        list_b.selection_clear(0,'end')
        list_b.selection_set(idx)
        list_b.activate(idx)
        return 'break'

def move_up():
    try:
        idx = list_b.curselection()[0]
        list_b.selection_clear(0,'end')
        list_b.selection_set(idx-1)
        list_b.activate(idx-1)
        return 'break'
    except IndexError:
        idx = list_b.size()
        list_b.selection_clear(0,'end')
        list_b.selection_set(idx-1)
        list_b.activate(idx-1)
        return 'break'
# Binding
list_b.bind('<Right>',lambda event:move_down()) 
list_b.bind('<Left>',lambda event: move_up())    

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