How to synchronize scroll bars of two grids in wx

Question

One custom wx.frame is created to place the splitter window with two grid controls inside. It was used to compare data in each grid. At this point, the scroll bar of the two grids should support synchronization.

Questions:

• How to get these two grid scroll events? I tried to align the wx.EVT_SCROLL event in a frame, but failed. I am also trying to bind a scroll event in a custom grid control, it also failed.
• How to synchronize the scroll bar of two grids? The cousin's answer is the question mentioned, to use gridInstance.Scroll (row, col) to scroll the grid client window. But it does not contain the ability to synchronize the scrollbar.

Thanks so much for any suggestion.

Custom frame init method

    def __init__(self, parent):
        wx.Frame.__init__(self, parent, -1, title='', size=(640,480))
        main_panel = wx.Panel(self, -1)
        self.TBFLAGS = ( wx.TB_HORIZONTAL| wx.NO_BORDER| wx.TB_FLAT)
        self.controller = None
        self.isSyncScroll = True

        #hsizer = wx.BoxSizer(wx.VERTICAL)
        gsizer = wx.FlexGridSizer(rows = 1,
                                                    cols = 1,
                                                    vgap = 2,
                                                    hgap = 2)
        gsizer.AddGrowableRow(0)
        gsizer.AddGrowableCol(0)
        self.tb = self.init_toolbar()
        (sub_panel0, sub_panel1) = self.init_splitter(main_panel)
        self.grid0 = self.init_grid(sub_panel0)
        self.grid1 = self.init_grid(sub_panel1)
        self.init_status_bar()

        gsizer.Add(main_panel, 1, wx.EXPAND)
        self.SetSizer(gsizer)

        ico = wx.Icon(u'Compare.ico', wx.BITMAP_TYPE_ICO)
        self.SetIcon(ico)
        self.Maximize()

        #can't catch the scroll event at the frame
        self.Bind(wx.EVT_SCROLL, self.OnScroll, self.grid0)
        #self.Bind(wx.EVT_SCROLL, self.OnScroll)
        #self.Bind(wx.EVT_SCROLL, self.OnScroll, id=self.grid0.GetId())

Answer 1

The following code gets 2 scroll bars moving together when you grab one or the other.

Python version 2.7.3 and wxpython 2.9.4.0 and windows Xp.

import wx
import wx.grid as grid


class Frame(wx.Frame):
    def __init__(self, parent):
        wx.Frame.__init__(self, parent, -1, "Grid", size=(350, 250))
        self.grid = grid.Grid(self)
        self.grid.CreateGrid(20, 20)


class ScrollSync(object):
    def __init__(self, frame1, frame2):
        self.frame1 = frame1
        self.frame2 = frame2
        self.frame1.grid.Bind(wx.EVT_SCROLLWIN, self.onScrollWin1)
        self.frame2.grid.Bind(wx.EVT_SCROLLWIN, self.onScrollWin2)

    def onScrollWin1(self, event):
        if event.Orientation == wx.SB_HORIZONTAL:
            self.frame2.grid.Scroll(event.Position, -1)
        else:
            self.frame2.grid.Scroll(-1, event.Position)
        event.Skip()

    def onScrollWin2(self, event):
        if event.Orientation == wx.SB_HORIZONTAL:
            self.frame1.grid.Scroll(event.Position, -1)
        else:
            self.frame1.grid.Scroll(-1, event.Position)
        event.Skip()

if __name__ == '__main__':
    app = wx.App()
    frame1 = Frame(None)
    frame1.Show()
    frame2 = Frame(None)
    frame2.Show()
    ScrollSync(frame1, frame2)
    app.MainLoop()

Here is another version that uses a timer to check and set scroll positions, so it covers any scroll changes.

import wx
import wx.grid as grid


class Frame(wx.Frame):
    def __init__(self, parent):
        wx.Frame.__init__(self, parent, -1, "Grid", size=(350, 250))
        self.grid = grid.Grid(self)
        self.grid.CreateGrid(20, 20)


class ScrollSync(wx.EvtHandler):
    def __init__(self, frame1, frame2):
        super(ScrollSync, self).__init__()
        self.frame1 = frame1
        self.frame2 = frame2
        self.frame1ScrollPos = self.getFrame1Pos()
        self.frame2ScrollPos = self.getFrame2Pos()
        self.Bind(wx.EVT_TIMER, self.onTimer)
        self.timer = wx.Timer(self)
        self.timer.Start(20)

    def onTimer(self, event):
        if not self.frame1 or not self.frame2:
            self.timer.Stop()
            return
        if self.frame1ScrollPos != self.getFrame1Pos():
            self.frame1ScrollPos = self.getFrame1Pos()
            self.frame2.grid.Scroll(self.frame1ScrollPos)
        elif self.frame2ScrollPos != self.getFrame2Pos():
            self.frame2ScrollPos = self.getFrame2Pos()
            self.frame1.grid.Scroll(self.frame2ScrollPos)

    def getFrame1Pos(self):
        horizontal = self.frame1.grid.GetScrollPos(wx.SB_HORIZONTAL)
        vertical = self.frame1.grid.GetScrollPos(wx.SB_VERTICAL)
        return horizontal, vertical

    def getFrame2Pos(self):
        horizontal = self.frame2.grid.GetScrollPos(wx.SB_HORIZONTAL)
        vertical = self.frame2.grid.GetScrollPos(wx.SB_VERTICAL)
        return horizontal, vertical


if __name__ == '__main__':
    app = wx.App()
    frame1 = Frame(None)
    frame1.Show()
    frame2 = Frame(None)
    frame2.Show()
    ScrollSync(frame1, frame2)
    app.MainLoop()