Question

I’m trying to learn how to use the wxPython wxScrolledWindow class for a project, and I’ve run into a wall.

I’ve set up a program that makes a panel derived from the wxScrolledWindow class containing a list of controls; the panel’s client is intentionally too small to show all the controls at once. I’ve managed to get a scrollbar on the side of the panel, but clicking it does nothing. Furthermore, whenever I attempt to call one of the Scrollbar-related inherited functions from the object, I get a strange error:

Traceback (most recent call last):
  File "C:\Python27\Projects\Supervisor\test.py", line 69, in <module>
    frame = MyFrame(None, "Test Bench")
  File "C:\Python27\Projects\Supervisor\test.py", line 18, in __init__
    self.mainpanel = MyPanel(self)
  File "C:\Python27\Projects\Supervisor\test.py", line 62, in __init__
    self.SetScrollRate(10, 10)
  File "C:\Python27\lib\site-packages\wx-2.8-msw-unicode\wx\_windows.py", line 179, in SetScrollRate
    return _windows_.ScrolledWindow_SetScrollRate(*args, **kwargs)
TypeError: in method 'ScrolledWindow_SetScrollRate', expected argument 1 of type 'wxScrolledWindow *'

I’ve looked at a lot of examples, and I’m at a loss as to where I’m making the mistake.

I’m working in Python 2.7.3, wxPython 2.8, under MS Windows. I’ve actually managed to get a lot of things done without running into serious problems, and certainly nothing like this.

My code follows:

# Test.py
#
# Dummy file for testing things that are too complex to type into the shell
# directly.

import wx

class MyFrame(wx.Frame):

    def __init__(self, parent, title):
        wx.Frame.__init__(self, parent, title=title)

        self.SetSize((800, 500))
        self.Center()

        self.Bind(wx.EVT_CLOSE, self.OnClose)

        self.mainpanel = MyPanel(self)
        self.mainpanel.SetMaxSize(self.GetVirtualSize())

        sizer = wx.BoxSizer(wx.VERTICAL)
        sizer.Add(self.mainpanel)

        self.SetSizer(sizer)
        self.Show(True)

        mpsize = self.mainpanel.GetSize()
        mvsize = self.mainpanel.GetVirtualSize()
        vsize = self.GetVirtualSize()

        self.SetClientSize((mpsize[0], vsize[1]))
        self.mainpanel.SetSize((mpsize[0], vsize[1]))
        self.mainpanel.SetVirtualSize(mvsize)

    def OnClose(self, e):
        self.Destroy()


class MyPanel(wx.ScrolledWindow):

    def __init__(self, parent):

        wx.Panel.__init__(self, parent,
                          style = wx.VSCROLL)

        sizer = wx.GridBagSizer(10, 10)

        self.egps = []
        for i in range(20):
            leftbit = wx.StaticText(self, label = "Item " + str(i))
            midbit = wx.TextCtrl(self, id = wx.ID_ANY)
            rightbit = wx.CheckBox(self, id = wx.ID_ANY, label = "Checkbox")

            self.egps.append([leftbit, midbit, rightbit])

        for i in range(len(self.egps)):
            sizer.Add(self.egps[i][0], (i,0))
            sizer.Add(self.egps[i][1], (i,1))
            sizer.Add(self.egps[i][2], (i,2))

        self.SetSizer(sizer)
        self.SetScrollRate(10, 10)



if __name__ == "__main__":
    app = wx.App(False)

    frame = MyFrame(None, "Test Bench")

    app.MainLoop()

Answer 1

Okay, I feel kinda dumb. The problem, upon further review, is that I adapted the code from an old class inheriting from wx.Panel. As such, I have the wx.Panel.__init__… line instead of a wx.ScrolledWindow.__init__… line.

it’s funny, you stare at the code for a long time and don’t see it…but as soon as the post goes up, there it is. 😛