WPF Debugging AvalonEdit binding to Document property.
- by kubal5003
Hello,
all day long I am sitting and trying to find out why binding to AvalonEdits Document property isn't working. AvalonEdit is an advanced WPF text editor - part of the SharpDevelop project.(it's going to be used in SharpDevelop v4 Mirador).
So when I set up a simple project - one TextEditor (that's the AvalonEdits real name in the library) and made a simple class that has one property - Document and it returns a dummy object with some static text the binding is working perfectly.
However in real life solution I'm binding a collection of SomeEditor objects to TabControl.
TabControl has DataTemplate for SomeEditor and there's the TextEditor object.
<TabControl Grid.Column="1" x:Name="tabControlFiles" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" >
<TabControl.Resources>
<DataTemplate DataType="{x:Type m:SomeEditor}">
<a:TextEditor
Document="{Binding Path=Document, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, Converter={StaticResource NoopConverter}, IsAsync=True}"
x:Name="avalonEdit"></a:TextEditor>
</DataTemplate>
</TabControl.Resources>
<TabControl.ItemContainerStyle>
<Style BasedOn="{StaticResource TabItemStyle}" TargetType="{x:Type TabItem}">
<Setter Property="IsSelected" Value="{Binding IsSelected}"></Setter>
</Style>
</TabControl.ItemContainerStyle>
</TabControl>
This doesn't work. What I've investigated so far:
DataContext of TextEditor is set to the proper instance of SomeEditor
TextEditors Document property is set to some other instance than SomeEditor.Document property
when I set breakpoint to no-op converter that is attached to that binding it shows me the correct value for Document (the converter is used!)
I also dug through the VisualTree to obtain reference to TextEditor and called GetBindingExpression(TextEditor.DocumentProperty) and this did return nothing
WPF produces the following information:
System.Windows.Data Information: 10 : Cannot retrieve value using the binding and no valid fallback value exists; using default instead. BindingExpression:Path=Document; DataItem='SomeEditor' (HashCode=26280264); target element is 'TextEditor' (Name='avalonEdit'); target property is 'Document' (type 'TextDocument')
SomeEditor instance that is bound to already has a created and cached copy of Document before the binding occurs. The getter is never called.
Anyone can tell me what might be wrong? Why BindingExpression isn't set ? Why property getter is never called?
