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<p class=MsoPlainText>Dear Group,<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>I have a rather involved question (more accurately series
of questions) regarding WPF, particularly how it relates to DataBinding and
DataTemplates. I will do my best to keep this posting to a reasonable length,
but ... well ... I guess this serves somewhat as a warning ;) If you will
spare me a bit of background, I recently began trying to learn IronPython after
hearing an enthusiastic endorsement from a friend and colleague. While not a
programmer or computer scientist by training (on the opposite of the spectrum,
actually, my degree is in biomedical engineering); I have found myself
increasing needing to work with programming tools in the past few years. This
friend pointed me toward the .Net framework, and IronPython in particular as a
potential solution to several major issues we have been facing with our primary
data processing tool: Matlab.<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>As a trial test, I therefore decided to create a small
program in IronPython, namely, a Podcast Aggregator. I purchased a Manning
Early Access Program copy of Michael Foord's (excellent BTW) book, IronPython
in Action and started trying to work toward my small test project. As I also
wanted to learn WPF (not to mention make my little program as pretty as
possible), I decided to write the user interface for my aggregator in .xaml.<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>So, with that background out of the way, I arrive at a
few questions. The first of these is somewhat of a follow-up to a topic
addressed in May on this very list somewhat recently (reference: <a
href="http://lists.ironpython.com/pipermail/users-ironpython.com/2007-May/004912.html">http://lists.ironpython.com/pipermail/users-ironpython.com/2007-May/004912.html</a>).
In the original post, the author (Bish Bosh) asked what the best method of
referring to Python types in Xaml was. Later in the discussion, Dino Viehland
offered that it might be best to:<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>"Declare an interface in C# (or find an existing one
which has what you want) and inherit and implement the interfaces in Python.
Then the interface will be the bridge between the static and dynamic
worlds" (reference: <a
href="http://lists.ironpython.com/pipermail/users-ironpython.com/2007-May/004913.html">http://lists.ironpython.com/pipermail/users-ironpython.com/2007-May/004913.html</a>).<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>So, my first question: After reading all the material I
have been able to find on the subject, I have not been able to locate a good
tutorial or example of how this might be done. Might it be possible to get
some additional information on how this can be accomplished? A simple example
of how it can then be integrated into IronPython code would be extremely
appreciated.<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>I have made an effort using the information available in
the IronPython tutorial and a relatively simple XAML example (reference: <a
href="http://blah.winsmarts.com/2007-3-WPF__The_DataTemplate,_choosing_how_your_data_will_look_like.aspx">http://blah.winsmarts.com/2007-3-WPF__The_DataTemplate,_choosing_how_your_data_will_look_like.aspx</a>),
but I have had no luck in creating a test application that will successfully
load and perform as advertised.<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>Using the xaml, C# and mainWindow.py file below, I
receive the error:<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>SystemError: Type reference cannot find public type named
'LocalTimes'<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>I am at the end of my rope and am not sure what I should
try next. Are there any ideas on how I might successfully implement a custom
C# interface?<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>Sincerely,<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>Rob Oakes<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>PS, Here is the source code for the simple test case I
have been working with.<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText><< Main IPY script, called from command line with
ipy TestApp.py<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>import clr<o:p></o:p></p>
<p class=MsoPlainText>import os<o:p></o:p></p>
<p class=MsoPlainText>import WindowsRSS<o:p></o:p></p>
<p class=MsoPlainText>clr.AddReference("PresentationFramework")<o:p></o:p></p>
<p class=MsoPlainText>clr.AddReference("PresentationCore")<o:p></o:p></p>
<p class=MsoPlainText>clr.AddReferenceToFile("IFancyData.dll")<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>import LocalTimes, LocalTime<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>from System.IO import File<o:p></o:p></p>
<p class=MsoPlainText>from System.Windows.Markup import XamlReader from
System.ComponentModel import INotifyPropertyChanged from System.ComponentModel
import PropertyChangedEventArgs from System.Windows import Application, Window<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>class TestApp(object):<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText> def __init__(self):<o:p></o:p></p>
<p class=MsoPlainText> xamlStream =
File.OpenRead('DataBinding_20081102.xaml')<o:p></o:p></p>
<p class=MsoPlainText> self.Root = XamlReader.Load(xamlStream)<o:p></o:p></p>
<p class=MsoPlainText> self.LocalTimes = LocalTimes()<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>mainWin = TestApp()<o:p></o:p></p>
<p class=MsoPlainText>app = Application()<o:p></o:p></p>
<p class=MsoPlainText>app.Resources.Add('collection', LocalTimes())<o:p></o:p></p>
<p class=MsoPlainText>app.Run(mainWin.Root)<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>>><o:p> </o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText><< DataBinding_20081102.xaml - GUI Window<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText><Window xmlns="<a
href="http://schemas.microsoft.com/winfx/2006/xaml/presentation">http://schemas.microsoft.com/winfx/2006/xaml/presentation</a>"<o:p></o:p></p>
<p class=MsoPlainText> xmlns:x="<a
href="http://schemas.microsoft.com/winfx/2006/xaml">http://schemas.microsoft.com/winfx/2006/xaml</a>"<o:p></o:p></p>
<p class=MsoPlainText> Title="Hello World!" Height="300"
Width="300"><o:p></o:p></p>
<p class=MsoPlainText> <Window.Resources><o:p></o:p></p>
<p class=MsoPlainText> <ObjectDataProvider
x:Key="localTimes" ObjectType="{x:Type LocalTimes}"/><o:p></o:p></p>
<p class=MsoPlainText> </Window.Resources><o:p></o:p></p>
<p class=MsoPlainText> <Grid><o:p></o:p></p>
<p class=MsoPlainText> </Grid><o:p></o:p></p>
<p class=MsoPlainText></Window><o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>>><o:p> </o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText><< LocalTimes.cs - Custom C# Class - LocalTimes<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>using System;<o:p></o:p></p>
<p class=MsoPlainText>using System.Collections;<o:p></o:p></p>
<p class=MsoPlainText>using System.Collections.Generic;<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>public class LocalTimes : List<LocalTime> {<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText> public LocalTimes() {<o:p></o:p></p>
<p class=MsoPlainText> this.Add(new LocalTime("New York",
DateTime.Now));<o:p></o:p></p>
<p class=MsoPlainText> this.Add(new LocalTime("Chicago",
DateTime.Now.AddHours(-1)));<o:p></o:p></p>
<p class=MsoPlainText> this.Add(new LocalTime("Denver",
DateTime.Now.AddHours(-2)));<o:p></o:p></p>
<p class=MsoPlainText> this.Add(new LocalTime("Los
Angeles", DateTime.Now.AddHours(-3)));<o:p></o:p></p>
<p class=MsoPlainText> }<o:p></o:p></p>
<p class=MsoPlainText>}<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>public class LocalTime {<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText> private string place;<o:p></o:p></p>
<p class=MsoPlainText> private DateTime time;<o:p></o:p></p>
<p class=MsoPlainText> <o:p></o:p></p>
<p class=MsoPlainText> public LocalTime(string _place, DateTime _time) {<o:p></o:p></p>
<p class=MsoPlainText> <o:p></o:p></p>
<p class=MsoPlainText> place = _place;<o:p></o:p></p>
<p class=MsoPlainText> time = _time;<o:p></o:p></p>
<p class=MsoPlainText> }<o:p></o:p></p>
<p class=MsoPlainText> <o:p></o:p></p>
<p class=MsoPlainText> public DateTime Time {<o:p></o:p></p>
<p class=MsoPlainText> get { return time; }<o:p></o:p></p>
<p class=MsoPlainText> set { time = value; }<o:p></o:p></p>
<p class=MsoPlainText> }<o:p></o:p></p>
<p class=MsoPlainText> <o:p></o:p></p>
<p class=MsoPlainText> public string Place {<o:p></o:p></p>
<p class=MsoPlainText> <o:p></o:p></p>
<p class=MsoPlainText> get { return place; }<o:p></o:p></p>
<p class=MsoPlainText> }<o:p></o:p></p>
<p class=MsoPlainText>}<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>>><o:p> </o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText>Interpreter Output from the above files:<o:p></o:p></p>
<p class=MsoPlainText><o:p> </o:p></p>
<p class=MsoPlainText> File C:\Users\Rob
Oakes\AppData\IronPython\IPy-Tutorial\TestApp_20081102.py, line 23, in
Initialize<o:p></o:p></p>
<p class=MsoPlainText> File C:\Users\Rob
Oakes\AppData\IronPython\IPy-Tutorial\TestApp_20081102.py, line 20, in __init__<o:p></o:p></p>
<p class=MsoPlainText> File , line 0, in Load##106<o:p></o:p></p>
<p class=MsoPlainText> File PresentationFramework, line unknown, in Load<o:p></o:p></p>
<p class=MsoPlainText> File PresentationFramework, line unknown, in
XmlTreeBuildDefault<o:p></o:p></p>
<p class=MsoPlainText> File PresentationFramework, line unknown, in Parse<o:p></o:p></p>
<p class=MsoPlainText> File PresentationFramework, line unknown, in
ParseFragment<o:p></o:p></p>
<p class=MsoPlainText> File PresentationFramework, line unknown, in _Parse<o:p></o:p></p>
<p class=MsoPlainText> File PresentationFramework, line unknown, in ReadXaml<o:p></o:p></p>
<p class=MsoPlainText> File PresentationFramework, line unknown, in Read<o:p></o:p></p>
<p class=MsoPlainText>SystemError: Type reference cannot find public type named
'LocalTimes'.<o:p></o:p></p>
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