Tkinter - 如何停止在画布窗口上方滚动

Question

我有一个可滚动框架，鼠标滚轮绑定到滚动，但是当框架小于画布时，我可以在其上方滚动 - 如何将框架保持在画布顶部？这是代码的最小版本：import tkinter as tkclass Gui:    def __init__(self, master):        self.root = master        self.canvas = tk.Canvas(self.root)        self.frame = tk.Frame(self.canvas,bg='white')        self.scroll = tk.Scrollbar(self.canvas,orient='vertical', command=self.canvas.yview)        self.canvas.configure(yscrollcommand=self.scroll.set)        self.scroll.pack(side='right', fill='y')        self.canvas.place(relheight=1, relwidth=0.85, relx=0.15)        self.canvas_frame = self.canvas.create_window((0,0), window=self.frame, anchor='nw')        self.frame.bind('<Configure>', self.onFrameConfigure)        self.canvas.bind_all('<MouseWheel>', lambda event: self.canvas.yview_scroll(int(-1*(event.delta/120)), 'units'))        self.addToFrame()    def onFrameConfigure(self, event):        self.canvas.configure(scrollregion=self.canvas.bbox('all'))    def addToFrame(self):        self.label = tk.Label(self.frame,text='Label')        self.label.pack()        if __name__ == "__main__":    root = tk.Tk()    gui = Gui(root)    root.mainloop()

Answer 1

您可以定义自己的yview()方法，仅当画布的全部内容不可见时才进行滚动。为此，我使用了，如果所有画布内容都可见，self.canvas.yview()则返回。(0.0, 1.0)然后我使用自定义yview()方法作为滚动条命令和鼠标滚轮绑定。

import tkinter as tk

class Gui:

    def __init__(self, master):

        self.root = master

        self.canvas = tk.Canvas(self.root)

        self.frame = tk.Frame(self.canvas,bg='white')

        self.scroll = tk.Scrollbar(self.canvas,orient='vertical', command=self.yview)

        self.canvas.configure(yscrollcommand=self.scroll.set)

        self.scroll.pack(side='right', fill='y')

        self.canvas.place(relheight=1, relwidth=0.85, relx=0.15)

        self.canvas_frame = self.canvas.create_window((0,0), window=self.frame, anchor='nw')

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

        self.canvas.bind_all('<MouseWheel>', lambda event: self.yview('scroll', int(-1*(event.delta/120)), 'units'))

        self.addToFrame()

    def onFrameConfigure(self, event):

        self.canvas.configure(scrollregion=self.canvas.bbox('all'))

    def addToFrame(self):

        self.label = tk.Label(self.frame,text='Label')

        self.label.pack()

    def yview(self, *args):

        if self.canvas.yview() == (0.0, 1.0):

            return

        self.canvas.yview(*args)

if __name__ == "__main__":

    root = tk.Tk()

    gui = Gui(root)

    root.mainloop()