Question

我正在开发一个关于Tkinter，Python 2.7的应用程序。在我的一个进程中，我使用26个小部件构建了一部分窗口（根）： 23个标签，2个按钮和1个入口。在构建它们时，我不断将它们的名称添加到列表中以进一步销毁当他们的使用完成。为此，我按下其中一个按钮（“完成”）读取创建的列表并在“for”循环内destroy（）它们。小部件被不正常地销毁，而不是列表中的顺序。我需要按几下按钮即可完成。我发现，如果列表被反转（），我会发现沮丧，而不是洞察力 “for”循环在第一次尝试中都被“摧毁”。这是预期的行为吗？非常令人费解！我准备用奇怪的行为发布我的应用程序的部分除非有人已经知道它的原因，否则我会删除不必要的代码。我仍在用Python破坏我的排骨而不准备使用Classes ...... 谢谢！

我包括我的计划的相关部分。我编辑了原件以减小尺寸。测试了编辑后的版本，它具有相同的行为。我评论了一些代码，以显示纠正的位置。奥克利先生对此感兴趣。我不确定是否在转录我的代码时，正确的缩进没有受到影响。

我的代码：

# testdestroy.py
from Tkinter import *
root = Tk()
root.title('Information container')
root.geometry('1160x900+650+50')

global todestroy, screen, font1, lbl1txt, lbl2txt
global col, row, colincr, rowincr, bxincr, entries

todestroy = []
screen = ''
col = 10
row = 10
font1 = 'verdana 12 bold '
colincr = 370
rowincr = 40
bxincr = 145

entries = {' Last updated: ' : '11/08/2016 at 11:55',
            ' Login id: ' : 'calfucura',
            ' Password: ': 'munafuca',
            'card number' : '1234567890',
            'check number': '445',
            'expiry' : '12/06/2018',
            'PIN' : '9890', 
            'Tel:' : '1-800-234-5678',
            'emergency' : 'entry nine',
            'use for' : 'gas, groceries'}

def position(col, row, what):       # returns the position for the place command
    colincr = 370
    rowincr = 40
    bxincr = 145
    if what == 'down':
        row += rowincr
        col -= colincr
    if what == 'side':
        col += colincr
    if what == 'button1':
        row += rowincr
        col += colincr - bxincr
    if what == 'button':
        col -= bxincr
    if what == 'reset':
        col = col
        row = row
    return col, row

def done(event):                        #  Button "Done"
    print 'Done pressed'
    for name in todestroy:     # DOES NOT WORK!!!!
                               # THIS WORKS in the previous line: 
                               # for name in reversed(todestroy):
        name.destroy()
        todestroy.remove(name)

def accept(event):                      # Button "Accept"
    print 'Name to show: ', entry1.get()
    scr2d1(entries)

def scr2d():                            # Name to show
    lbl1txt = 'Enter name to show: '
    screen = 'scr2d'
    scr2(lbl1txt)
#    scr2d1(entries)

def scr2(lbl1txt):
    global todestroy, col, row, entry1
    lbl1 = Label(root, text = lbl1txt, anchor = E, width = 25, font = font1)
    entry1 = Entry(root, width = 25, show = '*', font = font1)
    Accept = Button(root, text = 'Accept', font = font1, bg = 'green', width = 9)
    cmd = eval('Accept'.lower())
    Accept.bind('<ButtonRelease-1>', cmd)
    col, row = position(200, 200, 'reset')
    lbl1.place(x = col, y = row)
    col, row = position(col, row, 'side')
    entry1.place(x = col , y = row )
    col, row = position(col, row, 'button1')
    Accept.place(x = col, y = row)
    todestroy = []
    todestroy.extend([lbl1, entry1, Accept])

def scr2d1(entries):                # show entries
    global todestroy, col, row
    lblup = 1
    lbl = 'lbl' + str(lblup)
    lbl = Label(root, text = 'Entry', font = font1, width = 20 )
    row = rowincr * 7
    col = 600
    col, row = position(col, row, 'down')
    lbl.place(x = col, y = row)
    todestroy.append(lbl)
    lblup += 1
    lbl = 'lbl' + str(lblup)
    lbl = Label(root, text = 'Contents', font = font1, width = 20)
    col, row = position(col, row, 'side')
    lbl.place (x = col, y = row)
    todestroy.append(lbl)
    for name in sorted(entries):
        lblup += 1
        lbl = 'lbl' + str(lblup)
        lbl = Label(root, text = name, bg = 'yellow', font = font1, width = 25, anchor = E)
        col, row = position(col, row, 'down')
        lbl.place(x = col, y = row)
        todestroy.append(lbl)
        lblup += 1
        lbl = 'lbl' + str(lblup)
        lbl = Label(root, text = entries[name], bg = 'yellow', font = font1, width = 25, anchor = W)
        col, row = position(col, row, 'side')
        lbl.place(x = col , y = row)
        todestroy.append(lbl)
    cmd = eval('done')
    Done = Button(root, text = 'Done', font = font1, bg = 'green', width = 9)
    Done.bind('<ButtonRelease-1>', cmd)
    col, row = position(col, row, 'button1')
    Done.place(x = col, y = row)
    todestroy.append(Done)

scr2d()

root.mainloop()

Answer 1

问题是你在迭代它时改变列表，这不是你应该做的事情。它与reversed一起使用的原因是因为您正在迭代原始列表的副本。如果使用for name in todestroy[:]，则会得到相同的结果，def done(event): global todestroy for name in todestroy: name.destroy() todestroy = []也会迭代列表的副本。

最快的解决方案是不从列表中删除任何内容，只需在删除所有内容后重置列表：

Frame

更好的解决方案是将您计划销毁的所有小部件放入HRESULT GetString(BSTR* p_bstrResult, unsigned long* ulErrCode) { HRESULT hr = S_OK; try { System::String ^systemstring = gcnew System::String(""); DotNetObject::o = gcnew DotNetObject:: DotNetObjectComponent(); *ulErrCode = (unsigned long)o->GetString(systemstring); pin_ptr<const wchar_t> wch = PtrToStringChars(systemstring); _bstr_t bstrt(wch); *p_bstrResult = bstrt.GetBSTR(); // native client babysits delete systemstring; } catch(Exception ^ ex) { } return hr; }。然后，您可以销毁该帧，它将销毁其所有子窗口小部件。

Tkinter对destroy（）的奇怪行为

1 个答案: