在没有root用户的情况下使用tkinter滚动条

Question

我有以下代码

import tkinter as tk
from tkinter import *
#------------------------------------------------------------------------------
class scrollPictures(Frame):
    def __init__(self, parent, *args, **kw):
        Frame.__init__(self, parent, *args, **kw)
        vsb = Scrollbar(self, orient=VERTICAL)
        vsb.pack(side=RIGHT, fill=Y, expand=False)
        canvas = Canvas(self, borderwidth=0, 
                             highlightthickness=0, yscrollcommand=vsb.set)
        canvas.pack(side=LEFT, fill=BOTH, expand=True)
        vsb.config(command = canvas.yview)

        canvas.xview_moveto(0)
        canvas.yview_moveto(0)

        self.interior = interior = Frame(canvas)
        interior_id = canvas.create_window(0,0, window=interior, anchor=NW)

        def _configure_interior(event):
            # update the scrollbars to match the size of the inner frame
            size = (interior.winfo_reqwidth(), interior.winfo_reqheight())
            print('in configure_interior %sx%s' % size)
            canvas.config(scrollregion="0 0 %s %s" % size)
            if interior.winfo_reqwidth() != canvas.winfo_width():
                # update the canvas's width to fit the inner frame
                canvas.config(width=interior.winfo_reqwidth())

        interior.bind('<Configure>', _configure_interior)

        def _configure_canvas(event):
            print('in configure_canvas %s %s  Canvas: %s %s' % 
                  (interior.winfo_reqwidth(), interior.winfo_reqheight(),
                    canvas.winfo_width(), canvas.winfo_height()))
            if interior.winfo_reqwidth() != canvas.winfo_width():
                # update the inner frame's width to fill the canvas
                print('Adjusting width')
                canvas.itemconfigure(interior_id, width=canvas.winfo_width())
        canvas.bind('<Configure>', _configure_canvas)

#------------------------------------------------------------------------------

print('Sandbox2')

def populate(frame):

    for row in range(100):
        tk.Label(frame, text="%s" % row, width=3, borderwidth="1", 
                 relief="solid").grid(row=int(row/4), column=2*(row % 4), padx = 10)
        t="this is the second column for row %s" %row
        tk.Label(frame, text=t).grid(row=int(row/4), column=2*(row % 4) + 1, padx = 5)

if __name__ == "__main__":
    root = tk.Tk()
    screenWidth = root.winfo_screenwidth()
    screenHeight = root.winfo_screenheight()
    root.geometry('%dx%d+%d+%d' % (int(0.75 * screenWidth), int(0.75 * screenHeight), 100, 5))

    root.title('Sandbox2')

    fr = Frame(root)

    scrollFrame = scrollPictures(root)

    populate(scrollFrame.interior)

    scrollFrame.grid(column = 0, row = 0, rowspan = 99, columnspan = 99)

    root.mainloop()

这紧随Mikails的回应。只要scrollFrame具有根目录作为主目录，一切就可以正常工作。但是将root更改为fr，我没有任何显示。

此外，如何将滚动区域的高度设置得更大，例如屏幕的下半部分。刚接触tkinter时，它的一些细微差别使我难以理解。