Tkinter网格管理器无法管理“顶层窗口”菜单

Question

So I've got a Python 3 and Tkinter app. I'm currently trying to add a menu bar to the top of the window it pops up in. It's fine creating, but as soon as I try to grid() it, it all goes haywire and throws me this error:

[first line omitted]
File "C:\Users\Me\Documents\sync.py", line 13 in __init__
  self.createWidgets()
File "C:\Users\Me\Documents\sync.py", line 21, in createWidgets
  self.menubar.grid(column = 0, comlumnspan = 3)
File "C:\Program Files (x86)\Python34\lib\tkinter\__init__.py", line 2020, in grid_configure + self._options(cnf,kw))
_tkinter.TclError: can't manage ".41452544.49048880": it's a top-level window

So from that, it's fairly obvious that the flow is working: __init__ calls createWidgets creates self.menubar , adds submenus, calls self.menubar.grid .

What I can't figure out is why Tkinter thinks the menubar it's being called to grid is a top-level window. self.menubar.grid() , being listed in the trace, is clearly the cause of the problem rather than the root window, so that must be what it's thinking.

Here's the bit of code in question:

def createWidgets(self):
    self.menubar = tk.Menu(self)
    self.menubar.grid(column = 0, columnspan = 3)

    SyncMenu = tk.Menu(self.menubar, tearoff = 0)
    SyncMenu.add_command(label = "Connect", command = self.Sync.Connect)
    SyncMenu.add_command(label = "Disconnect", command = self.Sync.Disconnect)

    FileMenu = tk.Menu(self.menubar, tearoff = 0)
    FileMenu.add_command(label = "Upload File", command = self.File.Upload)
    FileMenu.add_command(label = "Browse Online Files", command = self.File.Browse)

    self.menubar.add_cascade(label = "Sync", menu = SyncMenu)
    self.menubar.add_cascade(label = "File", menu = FileMenu)

The same error comes up no matter where I put the call to grid() .

The other part of this problem is that I'm in Python 3 and the updated Tkinter, so no tk.Tk() for me. Instead, to initialise, I have this:

class Application(tk.Frame):
    def __init__(self, master=None):
        tk.Frame.__init__(self,master)
        self.grid()
        self.createWidgets()
        self.master.geometry("500x500")

Answer 1

You can't use grid on menus. Tkinter considers them a top-level window because they float above other windows.

The normal way to create a traditional menubar is to associate it with the menu attribute of the root window:

root = tk.Tk()
menubar = tk.Menu(root)
...
root.configure(menu=menubar)

Answer 2

I've figured it out. When I edited the question to add the second code block, I noticed the self.master.geometry line, to which I thought "That line affects the main window, couldn't I use that?"

The answer was yes, so the solution to finding the root window was just to use self.master , which is defined in my __init__ method by the supercall to tk.Frame.__init__ :

class Application(tk.Frame):
    def __init__(self, master=None):
        tk.Frame.__init__(self,master)    # This line defines self.master
        self.grid()
        self.createWidgets()
        self.master.geometry("500x500")   # This line uses it

So the solution to get my menubar into the correct window is now this:

self.master["menu"] = self.menubar

which is in the code after creating all the menu and menu items.