title: Tkinter Listbox "update" or "refresh"
body: <p>I have made a simple GUI with a Entry for input, a button to save the input to an ini file. And for the hole purpose with this post is in the listbox I have added. How is it possible to refresh/update the listbox ? If I enter my name and hit save, the file is generated and stored in the folder. But the list dosent update in the GUI. </p>
  
  <p>I want the listbox to show the new files added, when the GUI i open. Mabye a button that updates the GUI ? </p>
  
  <pre><code>enter code here root 
  
  root = Tk()
  root.geometry('400x300')
  
  L1 = Label(root, text='Input')
  L1.place(x=10, y=10)
  
  e1 = Entry(root)
  e1.place(x=10, y=40)
  
  def SaveInput():
  config = configparser.ConfigParser()
  config.add_section("DATA")
  config.set("DATA", "NAME", e1.get())
  list_files = os.listdir(os.getcwd())
  list_numbers = [int(x[:-4]) for x in list_files if x.endswith(".ini")]
  
  if len(list_numbers) != 0:
  
      new_file_num = max(list_numbers) + 1
  
  else:
      new_file_num = 1
  
  new_file_name = str(new_file_num) + ".ini"
  
  with open(new_file_name, "w") as file_obj:
      config.write(file_obj)
  
  L1 = Listbox(root, height=5, width=50)
  L1.place(x=10, y=100)
  # LISTBOX
  def get_filenames():
  path = "C:/Users/ita9bi/Desktop/Test list"
  return os.listdir(path)
  
  for filename in get_filenames():
  L1.insert(END, filename)
  
  B1 = Button(root, text='Save', command=SaveInput)
  B1.place(x=10, y=60)
  
  
  
  root.mainloop()
  </code></pre>