wx.ListCtrl item max text length

Hello everyone,

I’m using a wxListCtrl as a log viewer. The logs typically range from 100k to 1000k lines. Each line is displayed as a single item in a one-column list, with some lines colored based on keywords.

I’ve noticed that long log lines are getting cut off, even though the column width is sufficient. The text simply stops at a certain point, leaving empty space in the column.

Is there a maximum length for text display in wxListCtrl? If so, is it adjustable? Given my use case, is there perhaps another widget that would be more suitable for displaying large logs?

XXX_Testingplayground.py (1.2 KB)
I add an example to run. Im running version (4, 2, 1, ‘’).

When I run your code using wxPython 4.2.2 gtk3 (phoenix) wxWidgets 3.2.6 + Python 3.12.3 + Linux Mint 22, it displays the full text in the ListCtrl.

Just to confirm. This is what i see. But you see the full text? I run it on windows 10 Python 3.12.4.

I’ve the same on Windows, so what about pythons textwrap and when it’s wrapped select and bring up a wx.PopupWindow :rofl:

Is the purpose of the application just to display the log messages for the user to read, or were you intending to provide additional functionality for the user to interact with the messages?

If it is the former, then I would suggest using one of the text controls: wx.TextCtrl, wx.richtext.RichTextCtrl or wx.stc.StyledTextCtrl.

Edit: add example using wx.TextCtrl

import wx

class MyFrame(wx.Frame):
    def __init__(self, *args, **kwds):
        wx.Frame.__init__(self, *args, **kwds)
        self.SetSize((1920, 200))
        self.SetTitle("No wrap TextCtrl")
        self.panel = wx.Panel(self, wx.ID_ANY)
        sizer = wx.BoxSizer(wx.VERTICAL)
        self.text_ctrl = wx.TextCtrl(self.panel, wx.ID_ANY, "", style=wx.HSCROLL | wx.TE_MULTILINE | wx.TE_READONLY)
        sizer.Add(self.text_ctrl, 1, wx.EXPAND|wx.ALL, 5)
        self.panel.SetSizer(sizer)
        self.Layout()

        default_style = wx.TextAttr("BLACK")
        warning_style = wx.TextAttr("RED")

        long_text = ("Lorem ipsum dolor sit amet, consetetur sadipscing elitr, "
                     "sed diam nonumy eirmod tempor invidunt ut labore et dolore "
                     "magna aliquyam erat, sed diam voluptua. At vero eos et "
                     "accusam et justo duo dolores et ea rebum. Stet clita kasd "
                     "gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet.")

        for i in range(5):
            if i == 2:
                self.text_ctrl.SetDefaultStyle(warning_style)
            else:
                self.text_ctrl.SetDefaultStyle(default_style)
            self.text_ctrl.AppendText(long_text+'\n')


if __name__ == "__main__":
    app = wx.App()
    frame = MyFrame(None)
    frame.Show()
    app.MainLoop()

So the issue is that it gets wraped by some windows setting?

I can not use textctrl because i have additional functionality. I also introduce copying the string with ctrl+c and found that when i do it i get the whole text.

I don’t think the text is wrapped (one would have to get it again), but there ar plenty of ways to show temporarily a shortend text in the context of a list control (after all the list control is only the opener to the list)
but if you are happy be pleased :innocent:

Does the UltimateListCtrl show the full text on Windows?

import wx
import wx.lib.agw.ultimatelistctrl as ULC

class MyFrame(wx.Frame):
    def __init__(self, *args, **kw):
        super(MyFrame, self).__init__(*args, **kw)

        panel = wx.Panel(self)

        self.list_ctrl = ULC.UltimateListCtrl(panel, wx.ID_ANY, agwStyle=ULC.ULC_REPORT)

        self.list_ctrl.InsertColumn(0, 'Log Messages')

        long_text = ("Lorem ipsum dolor sit amet, consetetur sadipscing elitr, "
                     "sed diam nonumy eirmod tempor invidunt ut labore et dolore "
                     "magna aliquyam erat, sed diam voluptua. At vero eos et "
                     "accusam et justo duo dolores et ea rebum. Stet clita kasd "
                     "gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet.")

        self.list_ctrl.InsertStringItem(0, long_text)

        self.list_ctrl.SetColumnWidth(0, 2500)

        sizer = wx.BoxSizer(wx.VERTICAL)
        sizer.Add(self.list_ctrl, 1, wx.EXPAND | wx.ALL, 5)
        panel.SetSizer(sizer)

        # self.ShowFullScreen(True)

class MyApp(wx.App):
    def OnInit(self):
        frame = MyFrame(None, title="UltimateListCtrl", size=(1900, 300))
        frame.Show()
        return True

if __name__ == "__main__":

    print(wx.VERSION)
    app = MyApp(False)
    app.MainLoop()

I am no C++ expert, but it seems to me that the MSW implementation of wx.ListCtrl has a hardcoded limit of 512 characters in setting/getting items. See for example here:

Maybe if the OP can measure how many characters get displayed we may have a confirmation of that.

The Linux version has no such problem as it uses the generic version of wx.ListCtrl, which does not have any limits in that sense - I know because I have used that as a base to create UltimateListCtrl.

You can try @RichardT suggestion on UltimateListCtrl, but I’m not sure the performances will be great with 100,000+ items.

Ultimately, I agree with all the other posters that a list control may not be the best tool for this job.

Perhaps you could use a Grid control with a single column? It appears to handle (on linux at least) large numbers of entries. It also has built in support for Ctrl+C to copy the contents of the selected rows to the clipboard as long as there is either a single selected row or a single selected block of contiguous rows. If there are more than one non-contiguous selected rows or blocks, a warning dialog is displayed.

import wx
import wx.grid

class MyFrame(wx.Frame):
    def __init__(self, *args, **kwds):
        wx.Frame.__init__(self, *args, **kwds)
        self.SetSize((1900, 300))
        self.SetTitle("Grid Control")
        self.panel = wx.Panel(self, wx.ID_ANY)
        sizer = wx.BoxSizer(wx.VERTICAL)
        self.grid = wx.grid.Grid(self.panel, wx.ID_ANY)
        self.grid.CreateGrid(0, 1)
        self.grid.SetRowLabelSize(0)
        self.grid.SetColLabelSize(30)
        self.grid.SetDefaultColSize(1900, True)
        self.grid.EnableEditing(0)
        self.grid.EnableDragRowSize(0)
        self.grid.SetSelectionMode(wx.grid.Grid.SelectRows)
        self.grid.SetColLabelValue(0, "Log Messages")
        sizer.Add(self.grid, 1, wx.EXPAND, 0)
        self.panel.SetSizer(sizer)
        self.Layout()

        long_text = ("Lorem ipsum dolor sit amet, consetetur sadipscing elitr, "
                     "sed diam nonumy eirmod tempor invidunt ut labore et dolore "
                     "magna aliquyam erat, sed diam voluptua. At vero eos et "
                     "accusam et justo duo dolores et ea rebum. Stet clita kasd "
                     "gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet.")

        num_rows = 100000
        self.grid.AppendRows(num_rows)
        for r in range(num_rows):
            self.grid.SetCellValue(r, 0, f"{r} {long_text}")
        self.grid.GoToCell(num_rows-1, 0)
        self.grid.Refresh()
        self.grid.Update()


if __name__ == "__main__":
    app = wx.App()
    frame = MyFrame(None)
    frame.Show()
    app.MainLoop()

Screenshot at 2024-10-22 20-39-47

Below is an attempt at overriding the built in Ctrl+C handler to support non-contiguous rows. It appears to work on linux.

import wx
import wx.grid

class MyFrame(wx.Frame):
    def __init__(self, *args, **kwds):
        wx.Frame.__init__(self, *args, **kwds)
        self.SetSize((1900, 300))
        self.SetTitle("Grid Control")
        self.panel = wx.Panel(self, wx.ID_ANY)
        sizer = wx.BoxSizer(wx.VERTICAL)
        self.grid = wx.grid.Grid(self.panel, wx.ID_ANY)
        self.grid.CreateGrid(0, 1)
        self.grid.SetRowLabelSize(0)
        self.grid.SetColLabelSize(30)
        self.grid.SetDefaultColSize(1900, True)
        self.grid.EnableEditing(0)
        self.grid.EnableDragRowSize(0)
        self.grid.SetSelectionMode(wx.grid.Grid.SelectCells)
        self.grid.SetColLabelValue(0, "Log Messages")
        sizer.Add(self.grid, 1, wx.EXPAND, 0)
        self.panel.SetSizer(sizer)
        self.Layout()

        long_text = ("Lorem ipsum dolor sit amet, consetetur sadipscing elitr, "
                     "sed diam nonumy eirmod tempor invidunt ut labore et dolore "
                     "magna aliquyam erat, sed diam voluptua. At vero eos et "
                     "accusam et justo duo dolores et ea rebum. Stet clita kasd "
                     "gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet.")

        num_rows = 100000
        self.grid.AppendRows(num_rows)
        for r in range(num_rows):
            self.grid.SetCellValue(r, 0, f"{r} {long_text}")
        self.grid.GoToCell(num_rows-1, 0)
        self.grid.Refresh()
        self.grid.Update()

        self.grid.Bind(wx.EVT_KEY_DOWN, self.OnChar)


    def OnChar(self, event):
        keycode = event.GetKeyCode()
        if event.GetModifiers() == wx.MOD_CONTROL:
            if keycode == ord('C'):
                rows = self.grid.GetSelectedRows()
                text_list = [self.grid.GetCellValue(row, 0) for row in rows]
                text = "\n".join(text_list)
                clip_data = wx.TextDataObject()
                clip_data.SetText(text)
                wx.TheClipboard.Open()
                wx.TheClipboard.SetData(clip_data)
                wx.TheClipboard.Close()
            else:
                event.Skip()
        else:
            event.Skip()


if __name__ == "__main__":
    app = wx.App()
    frame = MyFrame(None)
    frame.Show()
    app.MainLoop()

It appears that only 259 characters are being displayed, resulting in a total of 260 characters, including the escape character. Interestingly, this matches the maximum Windows path length (260 characters), which corresponds to a known Windows API limitation. Although it’s possible to modify the registry to support longer paths, this solution doesn’t always work. I once experienced a situation where I could create a file with a longer name but was unable to use it afterward.

I’ll check out the other widgets mentioned, probably not today but later. One key requirement is background color coding. Performance has always been an issue—loading a log with some 100,000 lines took up to 30 seconds. So this might be the tipping point to switch. Thanks again.

I just did some timings on my linux PC.

For the UltimateListCtrl - adding 10000 long messages took 51.8 seconds.
For the Grid control - adding 100000 long messages took 0.4 seconds!

The code below shows how to conditionally change a Grid cell’s colours:

import wx
import wx.grid

class MyFrame(wx.Frame):
    def __init__(self, *args, **kwds):
        wx.Frame.__init__(self, *args, **kwds)
        self.SetSize((1900, 220))
        self.SetTitle("Grid Control")
        self.panel = wx.Panel(self, wx.ID_ANY)
        sizer = wx.BoxSizer(wx.VERTICAL)
        self.grid = wx.grid.Grid(self.panel, wx.ID_ANY)
        self.grid.CreateGrid(0, 1)
        self.grid.SetRowLabelSize(0)
        self.grid.SetColLabelSize(30)
        self.grid.SetDefaultColSize(1900, True)
        self.grid.EnableEditing(0)
        self.grid.EnableDragRowSize(0)
        self.grid.SetSelectionMode(wx.grid.Grid.SelectRows)
        self.grid.SetColLabelValue(0, "Log Messages")
        sizer.Add(self.grid, 1, wx.EXPAND, 0)
        self.panel.SetSizer(sizer)
        self.Layout()

        long_text = ("Lorem ipsum dolor sit amet, consetetur sadipscing elitr, "
                     "sed diam nonumy eirmod tempor invidunt ut labore et dolore "
                     "magna aliquyam erat, sed diam voluptua. At vero eos et "
                     "accusam et justo duo dolores et ea rebum. Stet clita kasd "
                     "gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet.")

        num_rows = 5
        self.grid.AppendRows(num_rows)
        for r in range(num_rows):
            self.grid.SetCellValue(r, 0, f"{r} {long_text}")
            if r in (1, 3):
                self.grid.SetCellTextColour(r, 0, '#FF0000')
                self.grid.SetCellBackgroundColour(r, 0, '#D0F0A0')

        self.grid.Refresh()
        self.grid.Update()


if __name__ == "__main__":
    app = wx.App()
    frame = MyFrame(None)
    frame.Show()
    app.MainLoop()

1 Like

I’m using ListCtrl to display a Python object dictionary (keys and values). Some of the object, such as __builtins__, have long string expressions and may need more than 10k ~ 100k chars to represent it.
So it’s not a problem but natural that the text in the list control items gets truncated.

If you still care about displaying the entire text, @RichardT’s solution using wx.grid is nice.
If you don’t, you will be happy with ListCtrl; DataViewListCtrl can be another option.

Here’s what it looks like:

import wx
import wx.dataview as dv

class MyFrame(wx.Frame):
    def __init__(self, *args, **kw):
        super(MyFrame, self).__init__(*args, **kw)

        panel = wx.Panel(self)

        ## self.list_ctrl = wx.ListCtrl(panel, style=wx.LC_REPORT)
        self.list_ctrl = dv.DataViewListCtrl(panel)

        ## self.list_ctrl.InsertColumn(0, 'Log Messages')
        self.list_ctrl.AppendTextColumn('Log Messages')
        
        long_text = ("Lorem ipsum dolor sit amet, consetetur sadipscing elitr, "
                     "sed diam nonumy eirmod tempor invidunt ut labore et dolore "
                     "magna aliquyam erat, sed diam voluptua. At vero eos et "
                     "accusam et justo duo dolores et ea rebum. Stet clita kasd "
                     "gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet.")

        ## self.list_ctrl.InsertItem(0, long_text)
        self.list_ctrl.AppendItem([long_text])

        sizer = wx.BoxSizer(wx.VERTICAL)
        sizer.Add(self.list_ctrl, 1, wx.EXPAND | wx.ALL, 5)
        panel.SetSizer(sizer)

@RichardT - out of curiosity, did UltimateListCtrl take 52 seconds in virtual mode (I.e. with the wx.LC_VIRTUAL flag set)? That sounds a bit too long.

If it’s not in virtual mode, then of course it takes that long.

@Andrea_Gavana - yes, that timing for ULC was for non-virtual mode.

Below I have made a rough attempt to produce a virtual mode version.

I didn’t try to time it, but the frame appears very fast and the list is very responsive to scrolling.

import wx
import wx.lib.agw.ultimatelistctrl as ULC

class TestUltimateListCtrl(ULC.UltimateListCtrl):

    def __init__(self, parent, messages):
        ULC.UltimateListCtrl.__init__(self, parent, -1,
                                      agwStyle=wx.LC_REPORT|wx.LC_VIRTUAL|wx.LC_HRULES|wx.LC_VRULES)
        self.messages = messages
        self.InsertColumn(0, 'Log Messages')
        self.SetColumnWidth(0, 2500)
        self.SetItemCount(len(messages))

    def OnGetItemText(self, item, col):
        return self.messages[item]

    def OnGetItemTextColour(self, item, col):
        if item == 0:
            return wx.RED
        elif item == 4:
            return wx.GREEN
        elif item == 8:
            return wx.BLUE
        else:
            return None

    def OnGetItemToolTip(self, item, col):
        if item == 0:
            return "Tooltip: Item %d, column %d" % (item, col)
        return None


class MyFrame(wx.Frame):
    def __init__(self, *args, **kw):
        super(MyFrame, self).__init__(*args, **kw)
        panel = wx.Panel(self)

        long_text = ("Lorem ipsum dolor sit amet, consetetur sadipscing elitr, "
                     "sed diam nonumy eirmod tempor invidunt ut labore et dolore "
                     "magna aliquyam erat, sed diam voluptua. At vero eos et "
                     "accusam et justo duo dolores et ea rebum. Stet clita kasd "
                     "gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet.")
        num_rows = 100000
        messages = [f"{r} {long_text}" for r in range(num_rows)]
        self.list_ctrl = TestUltimateListCtrl(panel, messages)
        sizer = wx.BoxSizer(wx.VERTICAL)
        sizer.Add(self.list_ctrl, 1, wx.EXPAND | wx.ALL, 5)
        panel.SetSizer(sizer)


class MyApp(wx.App):
    def OnInit(self):
        frame = MyFrame(None, title="Virtual UltimateListCtrl", size=(1900, 300))
        frame.Show()
        return True

if __name__ == "__main__":
    app = MyApp(False)
    app.MainLoop()