How do I bind to a ListBox in IronPython?
I am just starting out using IronPython with WPF and I don't quiet understand how binding is supposed to be done.
Normally in WPF I would just do something like this:
<ListBox Name="MyListBox">
<ListBox.Resources>
<Style TargetType="ListBoxItem">
<Setter Property="ContentTemplate">
<Setter.Value>
<DataTemplate>
<DockPanel>
<Te开发者_如何学GoxtBlock Text="{Binding Path=From}" />
<TextBlock Text="{Binding Path=Subject}" />
</DockPanel>
</DataTemplate>
</Setter.Value>
</Setter>
</Style>
</ListBox.Resources>
</ListBox>
Then in my code behind:
MyListBox.ItemsSource = new ObservableCollection<Email>()
But in IronPython we cannot have an ObservableCollection of objects, only types. This does not work:
MyListBox.ItemsSource = new ObservableCollection[email]()
As it throws the Exception: "expected Array[Type], got classobj"
What am I supposed to do? Help please!
I worked this out myself, I had a few things wrong and was missing a few key point as well. I hope this answer can help someone else.
First was that you need pyevent.py from the tutorial/ directory in your IronPython directory.
Second we need a helper class:
class NotifyPropertyChangedBase(INotifyPropertyChanged):
"""INotifyProperty Helper"""
PropertyChanged = None
def __init__(self):
(self.PropertyChanged, self._propertyChangedCaller) = make_event()
def add_PropertyChanged(self, value):
self.PropertyChanged += value
def remove_PropertyChanged(self, value):
self.PropertyChanged -= value
def OnPropertyChanged(self, propertyName):
self._propertyChangedCaller(self, PropertyChangedEventArgs(propertyName))
Then you need to declare your data class like so:
class Email(NotifyPropertyChangedBase):
"""
use setter getter.
IronPython 2.6 or later.
"""
@property
def From(self):
return self._From
@From.setter
def From(self, value):
self._From = value
self.OnPropertyChanged("From")
@property
def Subject(self):
return self._Subject
@Subject.setter
def Subject(self, value):
self._Subject = value
self.OnPropertyChanged("Subject")
Finally set the ListBox's ItemSource:
self.data = ObservableCollection[Email]()
self.MyListBox.ItemsSource = self.data
Credit to this link for the help: http://palepoli.skr.jp/wp/2009/06/28/wpf-listview-databinding-for-ironpython/
Extending on boden's answer, you may want to enhance the NotifyPropertyChangedBase a bit:
class NotifyPropertyChangedBase(INotifyPropertyChanged):
PropertyChanged = None
def __init__(self):
self.PropertyChanged, self._propertyChangedCaller = pyevent.make_event()
def add_PropertyChanged(self, value):
self.PropertyChanged += value
def remove_PropertyChanged(self, value):
self.PropertyChanged -= value
def OnPropertyChanged(self, propertyName):
if self.PropertyChanged is not None:
self._propertyChangedCaller(self, PropertyChangedEventArgs(propertyName))
def init_view(self, view):
xaml = view
self.view = XamlLoader(xaml).Root
self.view.DataContext = self
def declareNotifiable(self, *symbols):
for symbol in symbols:
self.defineNotifiableProperty(symbol)
def defineNotifiableProperty(self, symbol):
dnp = """
import sys
sys.path.append(__file__)
from NotifyProperty import *
@notify_property
def {0}(self):
return self._{0}
@{0}.setter
def {0}(self, value):
self._{0} = value
""".format(symbol)
d = globals()
exec dnp.strip() in d
setattr(self.__class__, symbol, d[symbol])
exec("self.{0} = ''".format(symbol))
With that set, you could do sometihng like:
class Email(NotifyPropertyChangedBase):
def __init__(self):
self.defineNotifiableProperty("From", "Subject")
With that in place, you'll get the @notify_property and @property.setter items set for everything in the defineNotifiableProperty call.
IronPython is case-sensitive and does not use the new
keyword. Try:
MyListBox.ItemsSource = ObservableCollection[Email]()
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