python - 为什么我的 Frame 子类在 init 中抛出错误？

Question

我的程序如下:

from Tkinter import *
class TFrame(Frame):
    def __init__(self, master=None, cnf={}, **kw):
        Frame.__init__(self, master, cnf, kw)

if __name__ == '__main__':
    root = Tk()
    tf = TFrame(root)
    tf.pack()
    root.mainloop()

我得到这个错误:

Traceback (most recent call last):
  File "testFrame.py", line 11, in <module>
    tf = TFrame(root)
  File "testFrame.py", line 7, in __init__
    Frame.__init__(self, master, cnf, kw)
TypeError: __init__() takes at most 3 arguments (4 given)

我怎么会在这里得到一个TypeError？我做了类似的事情，比如 Tkinter.Label 类。

Frame类的代码在这里:

`class Frame(Widget):
    """Frame widget which may contain other widgets and can have a 3D border."""
    def __init__(self, master=None, cnf={}, **kw):
        """Construct a frame widget with the parent MASTER.

        Valid resource names: background, bd, bg, borderwidth, class,
        colormap, container, cursor, height, highlightbackground,
        highlightcolor, highlightthickness, relief, takefocus, visual, width."""
        cnf = _cnfmerge((cnf, kw))
        extra = ()
        if 'class_' in cnf:
            extra = ('-class', cnf['class_'])
            del cnf['class_']
        elif 'class' in cnf:
            extra = ('-class', cnf['class'])
            del cnf['class']
        Widget.__init__(self, master, 'frame', cnf, {}, extra)`

Answer 1

您需要在对 Frame.__init__ 的调用中解压 kw。

这应该适合你。

from Tkinter import *
class TFrame(Frame):
    def __init__(self, master=None, cnf={}, **kw):
        Frame.__init__(self, master, cnf, **kw)

if __name__ == '__main__':
    root = Tk()
    tf = TFrame(root)
    tf.pack()
    root.mainloop()

问题是 Frame 在其调用签名中使用了 **kw，它需要可变数量的关键字参数，但您正试图传递一个字典作为位置参数。