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It is definitely not necessary to call SetTopWindow() when there is only a single top level window and it is arguable whether it's useful to do it even when there are many of them so don't encourage its use in the documentation and also remove all its occurrences from the samples. Closes #12816. git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@66528 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
470 lines
16 KiB
C++
470 lines
16 KiB
C++
/////////////////////////////////////////////////////////////////////////////
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// Name: python.h
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// Purpose: topic overview
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// Author: wxWidgets team
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// RCS-ID: $Id$
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// Licence: wxWindows licence
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/////////////////////////////////////////////////////////////////////////////
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/**
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@page overview_python wxPython Overview
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This topic was written by Robin Dunn, author of the
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<a href="http://www.python.org/">wxPython</a> wrapper.
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@li @ref overview_python_what
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@li @ref overview_python_why
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@li @ref overview_python_othergui
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@li @ref overview_python_using
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@li @ref overview_python_classes
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@li @ref overview_python_help
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<hr>
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@section overview_python_what What is wxPython?
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wxPython is a blending of the wxWidgets GUI classes and the Python programming
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language.
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@subsection overview_python_what_py Python
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So what is Python? Go to http://www.python.org to learn more, but in a
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nutshell Python is an interpreted, interactive, object-oriented programming
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language. It is often compared to Tcl, Perl, Scheme or Java.
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Python combines remarkable power with very clear syntax. It has modules,
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classes, exceptions, very high level dynamic data types, and dynamic typing.
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There are interfaces to many system calls and libraries, and new built-in
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modules are easily written in C or C++. Python is also usable as an extension
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language for applications that need a programmable interface.
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Python is copyrighted but freely usable and distributable, even for commercial
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use.
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@subsection overview_python_what_wxpy wxPython
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wxPython is a Python package that can be imported at runtime that includes a
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collection of Python modules and an extension module (native code). It provides
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a series of Python classes that mirror (or shadow) many of the wxWidgets GUI
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classes. This extension module attempts to mirror the class hierarchy of
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wxWidgets as closely as possible. This means that there is a wxFrame class in
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wxPython that looks, smells, tastes and acts almost the same as the wxFrame
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class in the C++ version.
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wxPython is very versatile. It can be used to create standalone GUI
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applications, or in situations where Python is embedded in a C++ application as
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an internal scripting or macro language.
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Currently wxPython is available for Win32 platforms and the GTK toolkit (wxGTK)
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on most Unix/X-windows platforms. See the wxPython website http://wxPython.org/
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for details about getting wxPython working for you.
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@section overview_python_why Why Use wxPython?
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So why would you want to use wxPython over just C++ and wxWidgets? Personally I
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prefer using Python for everything. I only use C++ when I absolutely have to
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eke more performance out of an algorithm, and even then I usually code it as an
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extension module and leave the majority of the program in Python.
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Another good thing to use wxPython for is quick prototyping of your wxWidgets
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apps. With C++ you have to continuously go though the edit-compile-link-run
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cycle, which can be quite time consuming. With Python it is only an edit-run
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cycle. You can easily build an application in a few hours with Python that
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would normally take a few days or longer with C++. Converting a wxPython app to
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a C++/wxWidgets app should be a straight forward task.
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@section overview_python_othergui Other Python GUIs
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There are other GUI solutions out there for Python.
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@subsection overview_python_othergui_tkinter Tkinter
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Tkinter is the de facto standard GUI for Python. It is available on nearly
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every platform that Python and Tcl/TK are. Why Tcl/Tk? Well because Tkinter is
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just a wrapper around Tcl's GUI toolkit, Tk. This has it's upsides and it's
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downsides...
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The upside is that Tk is a pretty versatile toolkit. It can be made to do a lot
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of things in a lot of different environments. It is fairly easy to create new
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widgets and use them interchangeably in your programs.
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The downside is Tcl. When using Tkinter you actually have two separate language
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interpreters running, the Python interpreter and the Tcl interpreter for the
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GUI. Since the guts of Tcl is mostly about string processing, it is fairly slow
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as well. (Not too bad on a fast Pentium II, but you really notice the
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difference on slower machines.)
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It wasn't until the latest version of Tcl/Tk that native Look and Feel was
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possible on non-Motif platforms. This is because Tk usually implements its own
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widgets (controls) even when there are native controls available.
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Tkinter is a pretty low-level toolkit. You have to do a lot of work (verbose
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program code) to do things that would be much simpler with a higher level of
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abstraction.
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@subsection overview_python_othergui_pythonwin PythonWin
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PythonWin is an add-on package for Python for the Win32 platform. It includes
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wrappers for MFC as well as much of the Win32 API. Because of its foundation,
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it is very familiar for programmers who have experience with MFC and the Win32
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API. It is obviously not compatible with other platforms and toolkits.
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PythonWin is organized as separate packages and modules so you can use the
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pieces you need without having to use the GUI portions.
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@subsection overview_python_othergui_others Others
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There are quite a few other GUI modules available for Python, some in active
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use, some that haven't been updated for ages. Most are simple wrappers around
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some C or C++ toolkit or another, and most are not cross-platform compatible.
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See <a href="http://pypi.python.org/pypi?:action=browse&show=all&c=433">this link</a>
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for a listing of a few of them.
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@section overview_python_using Using wxPython
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I'm not going to try and teach the Python language here. You can do that at the
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<a href="http://www.python.org/doc/tut/tut.html">Python Tutorial</a>. I'm also
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going to assume that you know a bit about wxWidgets already, enough to notice
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the similarities in the classes used.
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Take a look at the following wxPython program. You can find a similar program
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in the @c wxPython/demo directory, named @c DialogUnits.py. If your Python and
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wxPython are properly installed, you should be able to run it by issuing this
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command:
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@code
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python DialogUnits.py
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@endcode
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@code
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01: ## import all of the wxPython GUI package
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02: from wxPython.wx import *
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03:
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04: ## Create a new frame class, derived from the wxPython Frame.
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05: class MyFrame(wxFrame):
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06:
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07: def __init__(self, parent, id, title):
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08: # First, call the base class' __init__ method to create the frame
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09: wxFrame.__init__(self, parent, id, title,
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10: wxPoint(100, 100), wxSize(160, 100))
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11:
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12: # Associate some events with methods of this class
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13: EVT_SIZE(self, self.OnSize)
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14: EVT_MOVE(self, self.OnMove)
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15:
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16: # Add a panel and some controls to display the size and position
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17: panel = wxPanel(self, -1)
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18: wxStaticText(panel, -1, "Size:",
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19: wxDLG_PNT(panel, wxPoint(4, 4)), wxDefaultSize)
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20: wxStaticText(panel, -1, "Pos:",
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21: wxDLG_PNT(panel, wxPoint(4, 14)), wxDefaultSize)
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22: self.sizeCtrl = wxTextCtrl(panel, -1, "",
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23: wxDLG_PNT(panel, wxPoint(24, 4)),
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24: wxDLG_SZE(panel, wxSize(36, -1)),
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25: wxTE_READONLY)
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26: self.posCtrl = wxTextCtrl(panel, -1, "",
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27: wxDLG_PNT(panel, wxPoint(24, 14)),
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28: wxDLG_SZE(panel, wxSize(36, -1)),
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29: wxTE_READONLY)
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30:
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31:
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32: # This method is called automatically when the CLOSE event is
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33: # sent to this window
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34: def OnCloseWindow(self, event):
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35: # tell the window to kill itself
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36: self.Destroy()
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37:
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38: # This method is called by the system when the window is resized,
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39: # because of the association above.
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40: def OnSize(self, event):
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41: size = event.GetSize()
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42: self.sizeCtrl.SetValue("%s, %s" % (size.width, size.height))
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43:
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44: # tell the event system to continue looking for an event handler,
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45: # so the default handler will get called.
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46: event.Skip()
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47:
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48: # This method is called by the system when the window is moved,
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49: # because of the association above.
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50: def OnMove(self, event):
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51: pos = event.GetPosition()
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52: self.posCtrl.SetValue("%s, %s" % (pos.x, pos.y))
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53:
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54:
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55: # Every wxWidgets application must have a class derived from wxApp
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56: class MyApp(wxApp):
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57:
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58: # wxWidgets calls this method to initialize the application
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59: def OnInit(self):
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60:
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61: # Create an instance of our customized Frame class
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62: frame = MyFrame(NULL, -1, "This is a test")
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63: frame.Show(true)
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64:
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67:
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68: # Return a success flag
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69: return true
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70:
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71:
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72: app = MyApp(0) # Create an instance of the application class
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73: app.MainLoop() # Tell it to start processing events
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74:
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@endcode
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@subsection overview_python_using_notice Things to Notice
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At line 2 the wxPython classes, constants, and etc. are imported into the
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current module's namespace. If you prefer to reduce namespace pollution you can
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use @c "from wxPython import wx" and then access all the wxPython identifiers
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through the wx module, for example, @c "wx.wxFrame".
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At line 13 the frame's sizing and moving events are connected to methods of the
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class. These helper functions are intended to be like the event table macros
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that wxWidgets employs. But since static event tables are impossible with
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wxPython, we use helpers that are named the same to dynamically build the
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table. The only real difference is that the first argument to the event helpers
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is always the window that the event table entry should be added to.
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Notice the use of @c wxDLG_PNT and @c wxDLG_SZE in lines 19-29 to convert from
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dialog units to pixels. These helpers are unique to wxPython since Python can't
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do method overloading like C++.
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There is an @c OnCloseWindow method at line 34 but no call to @c EVT_CLOSE to
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attach the event to the method. Does it really get called? The answer is, yes
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it does. This is because many of the standard events are attached to windows
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that have the associated standard method names. I have tried to follow the lead
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of the C++ classes in this area to determine what is standard but since that
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changes from time to time I can make no guarantees, nor will it be fully
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documented. When in doubt, use an @c EVT_*** function.
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At lines 17 to 21 notice that there are no saved references to the panel or the
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static text items that are created. Those of you who know Python might be
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wondering what happens when Python deletes these objects when they go out of
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scope. Do they disappear from the GUI? They don't. Remember that in wxPython
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the Python objects are just shadows of the corresponding C++ objects. Once the
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C++ windows and controls are attached to their parents, the parents manage them
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and delete them when necessary. For this reason, most wxPython objects do not
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need to have a @c __del__ method that explicitly causes the C++ object to be
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deleted. If you ever have the need to forcibly delete a window, use the
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Destroy() method as shown on line 36.
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Just like wxWidgets in C++, wxPython apps need to create a class derived from
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@c wxApp (line 56) that implements a method named @c OnInit, (line 59.) This
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method should create the application's main window (line 62) and show it.
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And finally, at line 72 an instance of the application class is created. At
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this point wxPython finishes initializing itself, and calls the @c OnInit
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method to get things started. (The zero parameter here is a flag for
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functionality that isn't quite implemented yet. Just ignore it for now.) The
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call to @c MainLoop at line 73 starts the event loop which continues until the
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application terminates or all the top level windows are closed.
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@section overview_python_classes Classes Implemented in wxPython
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The following classes are supported in wxPython. Most provide nearly full
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implementations of the public interfaces specified in the C++ documentation,
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others are less so. They will all be brought as close as possible to the C++
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spec over time.
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@li wxAcceleratorEntry
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@li wxAcceleratorTable
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@li wxActivateEvent
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@li wxBitmap
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@li wxBitmapButton
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@li wxBitmapDataObject
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@li wxBMPHandler
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@li wxBoxSizer
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@li wxBrush
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@li wxBusyInfo
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@li wxBusyCursor
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@li wxButton
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@li wxCalculateLayoutEvent
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@li wxCalendarCtrl
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@li wxCaret
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@li wxCheckBox
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@li wxCheckListBox
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@li wxChoice
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@li wxClientDC
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@li wxClipboard
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@li wxCloseEvent
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@li wxColourData
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@li wxColourDialog
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@li wxColour
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@li wxComboBox
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@li wxCommandEvent
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@li wxConfigBase
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@li wxControl
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@li wxCursor
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@li wxCustomDataObject
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@li wxDataFormat
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@li wxDataObject
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@li wxDataObjectComposite
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@li wxDataObjectSimple
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@li wxDateTime
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@li wxDateSpan
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@li wxDC
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@li wxDialog
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@li wxDirDialog
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@li wxDragImage
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@li wxDropFilesEvent
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@li wxDropSource
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@li wxDropTarget
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@li wxEraseEvent
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@li wxEvent
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@li wxEvtHandler
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@li wxFileConfig
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@li wxFileDataObject
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@li wxFileDialog
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@li wxFileDropTarget
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@li wxFileSystem
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@li wxFileSystemHandler
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@li wxFocusEvent
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@li wxFontData
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@li wxFontDialog
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@li wxFont
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@li wxFrame
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@li wxFSFile
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@li wxGauge
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@li wxGIFHandler
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@li wxGLCanvas
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@li wxHtmlCell
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@li wxHtmlContainerCell
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@li wxHtmlDCRenderer
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@li wxHtmlEasyPrinting
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@li wxHtmlParser
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@li wxHtmlTagHandler
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@li wxHtmlTag
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@li wxHtmlWinParser
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@li wxHtmlPrintout
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@li wxHtmlWinTagHandler
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@li wxHtmlWindow
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@li wxIconizeEvent
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@li wxIcon
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@li wxIdleEvent
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@li wxImage
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@li wxImageHandler
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@li wxImageList
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@li wxIndividualLayoutConstraint
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@li wxInitDialogEvent
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@li wxInputStream
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@li @ref wxFileSystem "wxInternetFSHandler"
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@li wxJoystickEvent
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@li wxJPEGHandler
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@li wxKeyEvent
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@li wxLayoutAlgorithm
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@li wxLayoutConstraints
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@li wxListBox
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@li wxListCtrl
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@li wxListEvent
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@li wxListItem
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@li wxMask
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@li wxMaximizeEvent
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@li wxMDIChildFrame
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@li wxMDIClientWindow
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@li wxMDIParentFrame
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@li wxMemoryDC
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@li wxMemoryFSHandler
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@li wxMenuBar
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@li wxMenuEvent
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@li wxMenuItem
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@li wxMenu
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@li wxMessageDialog
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@li wxMetafileDC
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@li wxMiniFrame
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@li wxMouseEvent
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@li wxMoveEvent
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@li wxNotebookEvent
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@li wxNotebook
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@li wxPageSetupDialogData
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@li wxPageSetupDialog
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@li wxPaintDC
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@li wxPaintEvent
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@li wxPalette
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@li wxPanel
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@li wxPen
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@li wxPNGHandler
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@li wxPoint
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@li wxPostScriptDC
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@li wxPreviewFrame
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@li wxPrintData
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@li wxPrintDialogData
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@li wxPrintDialog
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@li wxPrinter
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@li wxPrintPreview
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@li wxPrinterDC
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@li wxPrintout
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@li wxProcess
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@li wxQueryLayoutInfoEvent
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@li wxRadioBox
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@li wxRadioButton
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@li wxRealPoint
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@li wxRect
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@li wxRegionIterator
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@li wxRegion
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@li wxSashEvent
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@li wxSashLayoutWindow
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@li wxSashWindow
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@li wxScreenDC
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@li wxScrollBar
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@li wxScrollEvent
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@li ::wxScrolledWindow
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@li wxScrollWinEvent
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@li wxShowEvent
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@li wxSingleChoiceDialog
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@li wxSizeEvent
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@li wxSize
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@li wxSizer
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@li wxSizerItem
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@li wxSlider
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@li wxSpinButton
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@li wxSpinEvent
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@li wxSplitterWindow
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@li wxStaticBitmap
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@li wxStaticBox
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@li wxStaticBoxSizer
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@li wxStaticLine
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@li wxStaticText
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@li wxStatusBar
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@li wxSysColourChangedEvent
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@li wxTaskBarIcon
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@li wxTextCtrl
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@li wxTextDataObject
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@li wxTextDropTarget
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@li wxTextEntryDialog
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@li wxTimer
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@li wxTimerEvent
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@li wxTimeSpan
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@li wxTipProvider
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@li wxToolBarTool
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@li wxToolBar
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@li wxToolTip
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@li wxTreeCtrl
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@li wxTreeEvent
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@li wxTreeItemData
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@li wxTreeItemId
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@li wxUpdateUIEvent
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@li wxValidator
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@li wxWindowDC
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@li wxWindow
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@li @ref wxFileSystem "wxZipFSHandler"
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@section overview_python_help Where to Go for Help
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Since wxPython is a blending of multiple technologies, help comes from multiple
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sources. See http://wxpython.org/ for details on various sources of help, but
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probably the best source is the wxPython-users mail list. You can view the
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archive or subscribe by going to http://wxpython.org/maillist.php
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Or you can send mail directly to the list using this address:
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wxpython-users@lists.wxwidgets.org
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*/
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