Tkinter PIL 图像不显示在函数内部

Question

我正在使用 Tkinter 在 Toplevel() 中显示图像，但是当我把它放在一个函数中时它不起作用（我知道这是非常初学者）

 # -*- coding: utf-8 -*-
import Tkinter
from Tkinter import *
import tkMessageBox
from tkMessageBox import *
import Image, ImageTk
import PIL.Image, PIL.ImageTk
import os
import subprocess


root = Tk()
root.title("Test")
quin=Toplevel()    
C = Tkinter.Canvas(quin, bg="white", height = 350, width = 350)   
directory=os.path.dirname(os.path.abspath(__file__))
filename=os.path.join(directory, 'un.png')
img=PIL.Image.open(filename)
tkimg=PIL.ImageTk.PhotoImage(img)
image = C.create_image(175,175,image=tkimg)
C.grid(row=5,column=5)
def Head():
     h1 = Label(root, text = "How to Secure a Computer", fg ="white", bg = "#00b8ff", width = 6,bd=2, height =2, font = "Arial", relief = RAISED)
     h1.grid(row= 0, column = 0, ipadx=122, pady=3, padx=5,columnspan=3)
def Mainmenu():
    menubar = Menu(root)
    filemenu = Menu(menubar, tearoff=0)
    filemenu.add_command(label="Exit", command=root.destroy)
    menubar.add_cascade(label="Options", menu=filemenu)
    helpmenu = Menu(menubar, tearoff=0)
    helpmenu.add_radiobutton(label="Help")
    helpmenu.add_radiobutton(label="User Manual Security Configuration Guide")
    menubar.add_cascade(label="Help", menu=helpmenu)
    root.config(menu=menubar)

def Mainbuttons():
    B1=Button(root,text="Services",height=2, width=6,bd=2, font = "Arial", fg = "#FFFFFF", bg = "#156cff",command=Services)
    B2=Button(root,text="Account Policies",height=2, width=6,bd=2, font = "Arial", fg = "#FFFFFF", bg = "#156cff")
    B3=Button(root,text="Firewall Config",height=2, width=6,bd=2, font = "Arial", fg = "#FFFFFF", bg = "#156cff")
    B4=Button(root,text="User Logon Time",height=2, width=6,bd=2, font = "Arial", fg = "#FFFFFF", bg = "#156cff")
    B5=Button(root,text="Security Policies",height=2, width=6,bd=2, font = "Arial", fg = "#FFFFFF", bg = "#156cff")
    B1.grid(row = 1, column = 0, ipadx=120,pady=2,padx=5)
    B2.grid(row = 1, column = 1, ipadx=120,pady=2,padx=5)
    B3.grid(row = 2, column = 1, ipadx=120,pady=2,padx=5)
    B4.grid(row = 2, column = 0, ipadx=120,pady=2,padx=5)
    B5.grid(row = 3, column = 0, ipadx=120,pady=2,padx=5)

def Services():
    serv=Toplevel()
    servcanv=Canvas(serv,height=250, width=250)
    servtext=Text(serv,width=26)
    servtext.insert(INSERT, "To start go to your start menu, in the search bar\ntype services.msc")
    servtext.grid(row=0, column=0)
    servcanv.grid(row=0, column=1)
    s = Tkinter.Canvas(serv, bg="white", height = 350, width = 350)   
    directory=os.path.dirname(os.path.abspath(__file__))
    filename=os.path.join(directory, 'un.png')
    img=PIL.Image.open(filename)
    tkimg=PIL.ImageTk.PhotoImage(img)
    image=s.create_image(175,175,image=tkimg)
    s.grid(row=5,column=5)





Mainmenu()
Mainbuttons()   
Head()
root.mainloop()

如您所见，用于显示图像的代码使用了两次，一次在函数内部，一次在函数外部。在外面它工作完美，但在里面它不起作用，它说变量图像已分配但从未使用过。

Answer 1

它在函数内部不起作用，因为 tkimg 在函数完成后被垃圾回收。您需要将图像绑定到不会被垃圾收集的变量中。例如全局变量，或 class 中的实例变量，而不是局部变量。

要使 tkimg 能够写入全局 tkimg，请在函数中使用 global tkimg。

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