How to write an event handler for the buttons or what-widgets-ever of wx.FileDialog?

wxPython Users
#1

Hello.

I have a question around wx.FileDialog.

I googled a short example, or how to use wx.FileDialog, like this.

#!/usr/bin/env python3

import wx

def onButton(event):
    print("Button pressed.")

app = wx.App()

frame = wx.Frame(None, -1, 'win.py')
frame.SetSize(0,0,200,50)

# Create open file dialog
openFileDialog = wx.FileDialog(frame, "Open", "", "", 
      "Python files (*.py)|*.py", 
       wx.FD_OPEN | wx.FD_FILE_MUST_EXIST)

openFileDialog.ShowModal()
print(openFileDialog.GetPath())
openFileDialog.Destroy()

スクリーンショット_2023-04-12_15-53-35
スクリーンショット_2023-04-12_15-53-35992×791 34.5 KB

As you know, onButton here means an event handler, however no binds to any buttons wx.FileDialog automatically creates here; in other words, this event handler is useless.
To bind a button to an event handler, we have to know the “Name” or the variable of buttons stated on the source code; however, we do not know the name of “widgets” that wx.FileDialog makes.
I have checked the statements such as:

  • wx.FileDialog
  • wx.FileDialogCustomize
  • wx.FileDialogCustomizeHook
  • wx.FIleDialogButton

,nonetheless, nothing is stated.
What I would like to know especially is wx.FD_OPEN or wx.FD_SAVE. They make typical pop-ups an OS make, but I do not know what kind of name of buttons or textctrls for event handlers.
Is there any resources stating around it, or could anybody give some examples?

Thanks.

#2

The normal way of using the wx.FileDialog is to check the value returned by the ShowModal() method. This will be an ID value. It will be set to wx.ID_OK if the Open button was pressed, or wx.ID_CANCEL if the Cancel button or the ‘x’ button on the frame’s decoration was pressed, or the Esc key was pressed.

Modifying your example:

import wx

app = wx.App()

frame = wx.Frame(None, -1, 'win.py')
frame.SetSize(0,0,200,50)

# Create open file dialog
openFileDialog = wx.FileDialog(frame, "Open", "", "",
      "Python files (*.py)|*.py",
       wx.FD_OPEN | wx.FD_FILE_MUST_EXIST)

result = openFileDialog.ShowModal()

if result == wx.ID_OK:
    print("OK")
elif result == wx.ID_CANCEL:
    print("Cancel")

print(openFileDialog.GetPath())

openFileDialog.Destroy()

See also: wx.FileDialog — wxPython Phoenix 4.2.0 documentation

#3

Hello, Mr. RichardT, and thanks for your replying.

O.K., wx.FileDialog.ShowModal() itself returns a value.
What I am interested now is something like this.
Usually, for instance, file dialogs are activated by pull-down menus.
With wxGlade, those functions would be relatively easily made.
wxGlade automatically , for example, creates a Python file like this:

#!/usr/bin/env python3
# -*- coding: UTF-8 -*-
#
# generated by wxGlade 1.0.4 on Wed Apr 12 17:29:10 2023
#

import wx

# begin wxGlade: dependencies
# end wxGlade

# begin wxGlade: extracode
# end wxGlade


class MyFrame(wx.Frame):
    def __init__(self, *args, **kwds):
        # begin wxGlade: MyFrame.__init__
        kwds["style"] = kwds.get("style", 0) | wx.DEFAULT_FRAME_STYLE
        wx.Frame.__init__(self, *args, **kwds)
        self.SetSize((400, 300))
        self.SetTitle("frame")

        # Menu Bar
        self.frame_menubar = wx.MenuBar()
        wxglade_tmp_menu = wx.Menu()
        item = wxglade_tmp_menu.Append(wx.ID_ANY, "item", "")
        self.Bind(wx.EVT_MENU, lambda evt: MyDialog(self).ShowModal(), item)
        self.frame_menubar.Append(wxglade_tmp_menu, "item")
        self.SetMenuBar(self.frame_menubar)
        # Menu Bar end

        self.panel_1 = wx.Panel(self, wx.ID_ANY)

        sizer_1 = wx.BoxSizer(wx.VERTICAL)

        sizer_1.Add((0, 0), 0, 0, 0)

        self.panel_1.SetSizer(sizer_1)

        self.Layout()

        # end wxGlade

# end of class MyFrame

class MyDialog(wx.Dialog):
    def __init__(self, *args, **kwds):
        # begin wxGlade: MyDialog.__init__
        kwds["style"] = kwds.get("style", 0) | wx.DEFAULT_DIALOG_STYLE
        wx.Dialog.__init__(self, *args, **kwds)
        self.SetTitle("dialog")
        self.Layout()
        # end wxGlade

# end of class MyDialog

class MyApp(wx.App):
    def OnInit(self):
        self.frame = MyFrame(None, wx.ID_ANY, "")
        self.SetTopWindow(self.frame)
        self.frame.Show()
        return True

# end of class MyApp

if __name__ == "__main__":
    app = MyApp(0)
    app.MainLoop()

Replacing wx.Dialog with wx.FileDialog is O.K. Replacing wx.DEFAULT_DIALOG_STYLE with wx.FD_SAVE or what-so-ever prepared is O.K.
The Menu Bar’s event handler would be something like this:

lambda evt: onMyDialog(self)

and this would activate the FileDialog.
The Event Handler as a function here is like this:

def onMyDialog(self):
    with MyDialog(self) as fileDialog:
        if fileDialog.ShowModal() == wx.ID_CANCEL:
            return
        elif fileDialog.ShowModal() == wx.ID_OK:
            print('OK')

Then… Yes, I am sort of stuck here, showing the pop-up twice!

Do I misunderstand anything here?

Thanks.

#4

In your onMyDialog() method, the dialog’s ShowModal() method will be called twice if the user doesn’t click on the Cancel button.

The possible values returned by ShowModal() are wx.ID_CANCEL and wx.ID_OK.

If the returned value is wx.ID_CANCEL, the event handler can just return without doing anything.

Otherwise the code can assume the returned value was wx.ID_OK and it can then get the pathname and do the appropriate action with the selected file.

    def onMyDialog(self):
        with wx.FileDialog(self, "Open", "", "",
                           "Python files (*.py)|*.py",
                           wx.FD_OPEN | wx.FD_FILE_MUST_EXIST) as fileDialog:
            if fileDialog.ShowModal() == wx.ID_CANCEL:
                return

            pathname = fileDialog.GetPath()
            print(pathname)
#5

Thanks, Mr. RichardT.
With your help, I barely complete an MVC GUI style experiment(I actually did not know how to send messages from wx.FileDialog by using PyPubSub).

CLI Style(Read-Eval-Print Loop):

#!/usr/bin/env python3

import os, pickle, re, sys

class Content(object):
    def __init__(self, title, artist, rating, ripped):
        self.title = title
        self.artist = artist
        self.rating = rating
        self.ripped = ripped
    def __repr__(self):
        return f'Title:  {self.title}\nArtist: {self.artist}\nRating: {self.rating}\nRipped: {self.ripped}\n'

class Env(object):
    def __init__(self, package, ls = [], fname="", flag = False):
        self.package = package
        self.ls = ls
        self.fname = fname
        self.flag = flag
    def __repr__(self):
        return f'<package: {self.package} list: {self.ls} filename: {self.fname} flag: {self.flag}>'

def install_package():
    def insert_value(arg, env):
        return Env(env.package, ls = [Content(*arg)] + env.ls, fname = env.fname)
    def select(arg, env):
        return Env(env.package, ls = env.ls, fname = env.fname, flag = True)
    def new_file(arg, env):
        with open(''.join(arg) + ".dat", "wb") as f:
            pass
        return Env(env.package, ls = env.ls, fname = arg)
    def open_file(arg, env):
        fname = ''.join(arg)
        with open(fname, "rb") as f:
            ls = pickle.load(f)
        return Env(env.package, ls = ls, fname = fname)
    def save_file(arg, env):
        if env.fname == '':
            return save_file_as('tmp.dat', env)
        else:
            os.rename(env.fname, env.fname + '.bak')
            with open(env.fname, "wb") as f:
                pickle.dump(env.ls, f)
            return Env(env.package, ls = env.ls, fname = env.fname)
    def save_file_as(arg, env):
        fname = ''.join(arg)
        with open(fname, "wb") as f:
            pickle.dump(env.ls, f)
        return Env(env.package, ls = env.ls, fname = fname)
    def delete(arg, env):
        return Env(env.package,
                   ls = [i for i in env.ls if i != env.ls[int(arg[0])]],
                   fname = env.fname)
    return {'insert_value': insert_value,
            'select': select,
            'new_file': new_file,
            'open_file': open_file,
            'save_file': save_file,
            'save_file_as': save_file_as,
            'quit': lambda arg, env: sys.exit(),
            'delete': delete}

# Eval
def interp(x, env):
    x = [i.strip() for i in re.split("\(|,|、|\)", x) if i != ""]
    return env.package[x[0]](x[1:], env)

# Print
def display(env):
    if env.flag:
        [print(i) for i in env.ls]
    # print(env) # デバッグ用
    return env

if __name__ == '__main__':
    env = display(Env(install_package()))
    while True:
        try:
            env = display(interp(input("simple database> "), env))
        except KeyError:
            env
        except ValueError:
            env
        except IndexError:
            env

GUI Style(MVC):

#!/usr/bin/env python3
# -*- coding: UTF-8 -*-
#
# generated by wxGlade 1.0.4 on Wed Apr 12 23:57:09 2023
#

import wx

# begin wxGlade: dependencies
# end wxGlade

# begin wxGlade: extracode
from pubsub import pub
from simple_database import Env, install_package, interp
import sys

class Controller(object):
    def __init__(self):
        pub.subscribe(self.read, "Controller")
        self.table = {"OnNewFile": "new_file({})",
                      "OnOpen": "open_file({})",
                      "OnSaveFile": "save_file",
                      "OnSaveFileAs": "save_file_as({})",
                      "OnQuit": "quit",
                      "OnAddCD": "insert_value({})"}
    def read(self, x, env):
        pub.sendMessage("Model.eval",
                        x = self.table[x[0]].format(", ".join(x[1:])),
                        env = env)

class Model(object):
    def __init__(self):
        pub.subscribe(self.eval, "Model")
    def eval(self, x, env):
        pub.sendMessage("View.SetProperties", env = interp(x, env))

def OnNewFile(self):
    with NewFile(self) as fileDialog:
        if fileDialog.ShowModal() == wx.ID_CANCEL:
            pass
        pub.sendMessage("Controller.read",
                        x = ["OnNewFile", fileDialog.GetPath()],
                        env = self.env)

def OnOpen(self):
    with OpenFile(self) as fileDialog:
        if fileDialog.ShowModal() == wx.ID_CANCEL:
            pass
        pub.sendMessage("Controller.read",
                        x = ["OnOpen", fileDialog.GetPath()],
                        env = self.env)

def OnSaveFileAs(self):
    with SaveFileAs(self) as fileDialog:
        if fileDialog.ShowModal() == wx.ID_CANCEL:
            pass
        pub.sendMessage("Controller.read",
                        x = ["OnSaveFileAs", fileDialog.GetPath()],
                        env = self.env)
# end wxGlade


class View(wx.Frame):
    def __init__(self, *args, **kwds):
        # begin wxGlade: View.__init__
        self.env = Env(install_package())
        kwds["style"] = kwds.get("style", 0) | wx.DEFAULT_FRAME_STYLE
        wx.Frame.__init__(self, *args, **kwds)
        self.SetSize((400, 300))
        self.SetTitle("Simple Database")

        # Menu Bar
        self.frame_menubar = wx.MenuBar()
        wxglade_tmp_menu = wx.Menu()
        item = wxglade_tmp_menu.Append(wx.ID_ANY, u"新規作成\tCtrl+N", "")
        self.Bind(wx.EVT_MENU, lambda event: OnNewFile(self), item)
        item = wxglade_tmp_menu.Append(wx.ID_ANY, u"開く...\tCtrl+O", "")
        self.Bind(wx.EVT_MENU, lambda event: OnOpen(self), item)
        item = wxglade_tmp_menu.Append(wx.ID_ANY, u"保存\tCtrl+S", "")
        self.Bind(wx.EVT_MENU, lambda event: pub.sendMessage('Controller.read', x = ['OnSaveFile'], env = self.env), item)
        item = wxglade_tmp_menu.Append(wx.ID_ANY, u"名前を付けて保存...\tShift+Ctrl+S", "")
        self.Bind(wx.EVT_MENU, lambda event: OnSaveFileAs(self), item)
        item = wxglade_tmp_menu.Append(wx.ID_ANY, "Quit\tCtrl+Q", "")
        self.Bind(wx.EVT_MENU, lambda event: pub.sendMessage('Controller.read', 'OnQuit'), item)
        self.frame_menubar.Append(wxglade_tmp_menu, u"ファイル")
        self.SetMenuBar(self.frame_menubar)
        # Menu Bar end

        sizer_1 = wx.BoxSizer(wx.VERTICAL)

        self.AddCD = wx.Button(self, wx.ID_ANY, "AddCD")
        sizer_1.Add(self.AddCD, 0, 0, 0)

        self.list_ctrl_1 = wx.ListCtrl(self, wx.ID_ANY, style=wx.LC_HRULES | wx.LC_REPORT | wx.LC_VRULES)
        self.list_ctrl_1.AppendColumn(u"タイトル", format=wx.LIST_FORMAT_LEFT, width=-1)
        self.list_ctrl_1.AppendColumn(u"アーティスト", format=wx.LIST_FORMAT_LEFT, width=-1)
        self.list_ctrl_1.AppendColumn(u"レーティング", format=wx.LIST_FORMAT_LEFT, width=-1)
        self.list_ctrl_1.AppendColumn(u"リップ", format=wx.LIST_FORMAT_LEFT, width=-1)
        sizer_1.Add(self.list_ctrl_1, 1, wx.EXPAND, 0)

        self.SetSizer(sizer_1)

        self.Layout()

        self.Bind(wx.EVT_BUTTON, lambda event: ControllerDialog(self).ShowModal(), self.AddCD)
        # end wxGlade
        pub.subscribe(self.SetProperties, 'View')
        
    def SetProperties(self, env):
        self.env = env
        self.list_ctrl_1.DeleteAllItems()
        [[self.list_ctrl_1.InsertItem(sys.maxsize, obj) if col == 0
          else self.list_ctrl_1.SetItem(index, col, obj) for col, obj
          in enumerate([item.title, item.artist, item.rating, item.ripped])]
          for index, item in enumerate(self.env.ls)]

# end of class View

class ControllerDialog(wx.Dialog):
    def __init__(self, *args, **kwds):
        # begin wxGlade: ControllerDialog.__init__
        self.env = args[0].env
        kwds["style"] = kwds.get("style", 0) | wx.DEFAULT_DIALOG_STYLE
        wx.Dialog.__init__(self, *args, **kwds)
        self.SetTitle("Add CD")

        sizer_1 = wx.BoxSizer(wx.VERTICAL)

        grid_sizer_1 = wx.GridSizer(4, 2, 0, 0)
        sizer_1.Add(grid_sizer_1, 1, wx.EXPAND, 0)

        Title = wx.StaticText(self, wx.ID_ANY, u"タイトル")
        grid_sizer_1.Add(Title, 0, wx.ALIGN_CENTER, 0)

        self.text_ctrl_1 = wx.TextCtrl(self, wx.ID_ANY, "")
        grid_sizer_1.Add(self.text_ctrl_1, 0, wx.ALIGN_CENTER, 0)

        Artist = wx.StaticText(self, wx.ID_ANY, u"アーティスト")
        grid_sizer_1.Add(Artist, 0, wx.ALIGN_CENTER, 0)

        self.text_ctrl_2 = wx.TextCtrl(self, wx.ID_ANY, "")
        grid_sizer_1.Add(self.text_ctrl_2, 0, wx.ALIGN_CENTER, 0)

        Rating = wx.StaticText(self, wx.ID_ANY, u"レーティング")
        grid_sizer_1.Add(Rating, 0, wx.ALIGN_CENTER, 0)

        self.text_ctrl_3 = wx.TextCtrl(self, wx.ID_ANY, "")
        grid_sizer_1.Add(self.text_ctrl_3, 0, wx.ALIGN_CENTER, 0)

        Ripped = wx.StaticText(self, wx.ID_ANY, u"リップ")
        grid_sizer_1.Add(Ripped, 0, wx.ALIGN_CENTER, 0)

        self.text_ctrl_4 = wx.TextCtrl(self, wx.ID_ANY, "")
        grid_sizer_1.Add(self.text_ctrl_4, 0, wx.ALIGN_CENTER, 0)

        sizer_2 = wx.StdDialogButtonSizer()
        sizer_1.Add(sizer_2, 0, wx.ALIGN_RIGHT | wx.ALL, 4)

        self.button_OK = wx.Button(self, wx.ID_OK, "")
        self.button_OK.SetDefault()
        sizer_2.AddButton(self.button_OK)

        self.button_CANCEL = wx.Button(self, wx.ID_CANCEL, "")
        sizer_2.AddButton(self.button_CANCEL)

        sizer_2.Realize()

        self.SetSizer(sizer_1)
        sizer_1.Fit(self)

        self.SetAffirmativeId(self.button_OK.GetId())
        self.SetEscapeId(self.button_CANCEL.GetId())

        self.Layout()

        self.Bind(wx.EVT_BUTTON, lambda event: self.OnAddCD(), self.button_OK)
        self.Bind(wx.EVT_BUTTON, lambda event: self.Destroy(), self.button_CANCEL)
        # end wxGlade
        
    def OnAddCD(self):
        pub.sendMessage('Controller.read',
                        x = ['OnAddCD',
                             self.text_ctrl_1.GetLineText(0),
                             self.text_ctrl_2.GetLineText(0),
                             self.text_ctrl_3.GetLineText(0),
                             self.text_ctrl_4.GetLineText(0)],
                        env = self.env)
        self.Destroy()

# end of class ControllerDialog

class NewFile(wx.FileDialog):
    def __init__(self, *args, **kwds):
        # begin wxGlade: NewFile.__init__
        self.env = args[0].env
        kwds["style"] = kwds.get("style", 0) | wx.FD_SAVE
        wx.FileDialog.__init__(self, *args, **kwds)
        self.SetTitle(u"新規作成")
        self.Layout()
        # end wxGlade

# end of class NewFile

class OpenFile(wx.FileDialog):
    def __init__(self, *args, **kwds):
        # begin wxGlade: OpenFile.__init__
        self.env = args[0].env
        kwds["style"] = kwds.get("style", 0) | wx.FD_OPEN
        wx.FileDialog.__init__(self, *args, **kwds)
        self.SetTitle(u"開く...")
        self.Layout()
        # end wxGlade

# end of class OpenFile

class SaveFileAs(wx.FileDialog):
    def __init__(self, *args, **kwds):
        # begin wxGlade: SaveFileAs.__init__
        self.env = args[0].env
        kwds["style"] = kwds.get("style", 0) | wx.FD_SAVE
        wx.FileDialog.__init__(self, *args, **kwds)
        self.SetTitle("SaveFileAs")
        self.Layout()
        # end wxGlade

# end of class SaveFileAs

class SimpleDatabase(wx.App):
    def OnInit(self):
        self.View = View(None, wx.ID_ANY, "")
        self.SetTopWindow(self.View)
        self.View.Show()
        return True

# end of class SimpleDatabase

if __name__ == "__main__":
    m = Model()
    SimpleDatabase = SimpleDatabase(0)
    c = Controller()
    SimpleDatabase.MainLoop()

To be honest, to use wx.ListCtrl was much more difficult than wx.FileDialog… It took a time to figure out what is happened.
This implementation is still incomplete('cause I do not know how to do with right clicks on wx.ListCtrl); however, my basic purpose was done successfully.
Anyway, thank you very much!!