Tkinter Menubar

window = tk.Tk()
window.title('my window')
window.geometry('500x500')

var1 = tk.StringVar()
l = tk.Label(window, bg='yellow', width=4, textvariable=var1)
l.pack()

window.mainloop()  # 不断刷新主窗口

menubar = tk.Menu(window)

filemenu = tk.Menu(menubar, tearoff=0)
menubar.add_cascade(label='File', menu=filemenu)
filemenu.add_command(label='New', command=do_job)
filemenu.add_command(label='Open', command=do_job)
filemenu.add_command(label='Save', command=do_job)
filemenu.add_separator()
filemenu.add_command(label='Exit', command=window.quit)
submenu = tk.Menu(filemenu)
filemenu.add_cascade(label='Import', menu=submenu, underline=0)
submenu.add_command(label="Submenu1", command=do_job)

editmenu = tk.Menu(menubar, tearoff=0)
menubar.add_cascade(label='Edit', menu=editmenu)
editmenu.add_command(label='Cut', command=do_job)
editmenu.add_command(label='Copy', command=do_job)
editmenu.add_command(label='Paste', command=do_job)

window.config(menu=menubar)

counter = 0
def do_job():
    global counter
    l.config(text='do '+ str(counter))
    counter+=1