如何绑定鼠标滚轮以使框架可从窗口内的任何位置滚动？

Question

我有只在滚动条区域滚动的框架。我正在尝试使其在窗口中的任何位置均可滚动，但无法用鼠标滚轮将其绑定。

import tkinter as tk

class Example(tk.Frame):
    def __init__(self, root):

        tk.Frame.__init__(self, root)
        self.canvas = tk.Canvas(root, borderwidth=0)
        self.frame = tk.Frame(self.canvas)
        self.vsb = tk.Scrollbar(root, orient="vertical", command=self.canvas.yview)
        self.canvas.configure(yscrollcommand=self.vsb.set)
        self.canvas.create_window((0,0), window=self.frame, anchor="nw", 
                                  tags="self.frame")

        self.vsb.pack(side="right", fill="y")
        self.canvas.pack()

        self.frame.bind("<Configure>", self.onFrameConfigure)

        self.rectanglesize()

    def rectanglesize(self):

        for idx in range(20 * 2):
            if idx % 2 == 0:
                tk.Label(self.frame, text="Size of rectangle:").grid(row=idx, column=0)
            tk.Entry(self.frame).grid(row=idx, column=1)


    def onFrameConfigure(self, event):
        '''Reset the scroll region to encompass the inner frame'''
        self.canvas.configure(scrollregion=self.canvas.bbox("all"),width=250,height=500)
    def onmousewheel(event):
        self.canvas.yview_scroll(-1*(event.delta/120), "units")   

if __name__ == "__main__":
    root=tk.Tk()
    Example(root).pack()

    root.mainloop()