Python tkinter-画布中的滚动条不工作

我搜索过堆栈溢出，但大多数解决方案似乎对我不起作用，或者答案不够清楚，我不知道应该在哪里/如何使用代码。 由于某种原因，AddSubject框架中的水平滚动条无法工作。如何使水平滚动条工作

这是我的密码：

import tkinter as tk
from tkinter import ttk
import tkinter.scrolledtext as tks

class Program(tk.Tk):        
    def __init__(self, *args, **kwargs):
        tk.Tk.__init__(self, *args, **kwargs)

        tk.Tk.iconbitmap(self, default = "")
        tk.Tk.wm_title(self, "")

        container = tk.Frame(self)
        container.pack(side="top", fill="both", expand=True)
        container.grid_rowconfigure(0, weight=1)
        container.grid_columnconfigure(0, weight=1)

        self.frames = {}
        for F in (SubjectHome, AddSubject):

            frame = F(container, self)
            self.frames[F] = frame
            frame.grid(row = 0, column = 0, sticky = "nsew")

        self.show_frame(SubjectHome)



    def show_frame(self,cont):
        frame = self.frames[cont]
        frame.tkraise()


class SubjectHome(tk.Frame):

    def __init__(self, parent, controller):

        tk.Frame.__init__(self, parent)

        ttk.Style().configure("TButton", padding=6, relief="flat", background="#ccc")

        name = tk.Label(self, text = "User: FirstName + LastName")
        name.pack(anchor="ne")

        pagename = tk.Label(self, text = "Subject Menu")
        pagename.pack(anchor="n")

        self.innerFrame = tk.Frame(self, bg="red")
        self.innerFrame.place(relx=.5, rely=.5, anchor="c")        


        view = ttk.Button(self.innerFrame, text = "View Subjects", command = lambda: controller.show_frame(ViewSubject))
        view.grid(row=0, sticky="W"+"E")

        add = ttk.Button(self.innerFrame, text = "Add Subjects", command = lambda: controller.show_frame(AddSubject))
        add.grid(row=1, sticky="W"+"E")


class AddSubject(tk.Frame):

    def __init__(self, parent, controller):

        tk.Frame.__init__(self, parent)

        name = tk.Label(self, text = "User: FirstName + LastName")
        name.pack(anchor="ne")

        pagename = tk.Label(self, text = "Add Subjects")
        pagename.pack(anchor="n")

        self.innerFrame = tk.Frame(self)
        self.innerFrame.place(relx=.5, rely=.5, anchor="c")

        canvas = tk.Canvas(self.innerFrame)

        self.firstFrame = tk.Frame(canvas)
        self.firstFrame.pack(anchor="n")

        info = tk.Label(self.innerFrame, text = "Information...\n Information....")
        info.pack()

        for x in range(5):
            pagename = tk.Label(self.firstFrame, text = "Unit Name")
            pagename.grid(row=0, column=x)
            self.text = tks.ScrolledText(self.firstFrame, width=50)
            self.text.grid(row=1, column=x ,sticky="E")

        scrollbar = tk.Scrollbar(self.innerFrame, orient="horizontal", command=canvas.xview)
        canvas.configure(xscrollcommand=scrollbar.set)
        scrollbar.pack(side="bottom", fill="x")
        canvas.pack(side="left", fill="both", expand=True) 

        back = ttk.Button(self.innerFrame, text = "Back", command = lambda: controller.show_frame(SubjectHome))
        back.pack(anchor="sw")

        next = ttk.Button(self.innerFrame, text = "Next")
        next.pack(anchor="se")


app = Program()
app.state('zoomed')
app.mainloop()

---

对于要在画布上滚动的小部件，必须使用将其添加到画布中。如果调用

pack

或

grid

或

place

将小部件放置在画布中，它们将不会滚动