调整表单大小会杀死表单滚动

Question

I have an base class which defines my common form functions, including scrolling.

I added form re-sizing capabilities to one of the descendants, and it has killed scrolling.

In the following extract the form is scrolling. If you un-comment the one line, it enables the form and fields to be re-sized as I want, but it scrolling is dead.

Can someone help please?

from Tkinter import * 
import ttk

class DisplayListWindow(Canvas):

    def __init__(self, parent=None, *args, **kw):
         Canvas.__init__(self,parent, borderwidth=0, *args, **kw)

        self.frame = Frame(self)
        vsb = Scrollbar(parent, orient="vertical", command=self.yview)
        self.configure(yscrollcommand=vsb.set)
        vsb.pack(side="right", fill="y")

        self.create_window((4,4), window=self.frame, anchor="nw", 
                              tags="self.frame")

        self.pack(side="left", fill="both", expand=True)

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

        #remaining code in this function is from descendant classes
        for i in range(1, 20, 1):
            ttk.Entry(master=self.frame, style='C.TEntry').grid(row = i, column = 0, sticky = NSEW)
            ttk.Entry(master=self.frame, style='C.TEntry').grid(row = i, column = 1, sticky = NSEW)
            self.frame.columnconfigure(1, weight=1)

        #the following line enables the re-sizing behaviour, but kills scrolling
        #self.frame.pack(side="left", fill="both", expand=True)   # <== problem     

    #----------------------------------------------------------------------        
    def OnFrameConfigure(self, event):
        '''Reset the scroll region to encompass the inner frame'''
        self.configure(scrollregion=self.bbox("all"))

DisplayListWindow().mainloop()

Answer 1

If you are using a frame inside a canvas for the purposes of scrolling, you must add it to the canvas using create_window -- you cannot add it using pack or grid . These two methods (create_window, versus pack or grid) are incompatible with each other.

If you want the frame to resize when the window resizes, you'll have to add code to manually resize it. You can do this by adjusting the width in your <Configure> callback.

For example:

def OnFrameConfigure(self, event):
    '''Reset the scroll region to encompass the inner frame'''
    width = self.winfo_width() - 8 # allow room for some padding
    self.itemconfigure("self.frame", width=width)
    self.configure(scrollregion=self.bbox("all"))

Notice how I compute what the width should be by getting the width of the canvas, and then I use that value to set the width of the frame. The height is left to be the natural height of the frame, so the vertical scrollbar should always reflect the complete contents of the frame.