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Revision as of 22:48, 12 October 2012 by influencer (Talk | contribs)

How to debug data binding problems on Windows Phone

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Often XAML elements with data binding show no data during development. This article shows one method how to find the source of this problem.

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Created: influencer (12 Oct 2012)
Last edited: influencer (12 Oct 2012)



If you use data binding in your Windows Phone application, during development you'll come to the point where you have linked everything together but data doesn't display correctly in your control.


What can you do? You can use an IValueConverter and set a breakpoint there. This way you can see what data arrives at your element and check the available properties.

Say you have a ListBox like this:

         <ListBox x:Name="MainListBox" Margin="0,0,-12,0" ItemsSource="{Binding Items}" SelectionChanged="MainListBox_SelectionChanged">
<StackPanel Margin="0,0,0,17" Width="432" Height="78">
<TextBlock Text="{Binding LineOne}" TextWrapping="Wrap" Style="{StaticResource PhoneTextExtraLargeStyle}"/>
<TextBlock Text="{Binding LineTwo}" TextWrapping="Wrap" Margin="12,-6,12,0" Style="{StaticResource PhoneTextSubtleStyle}"/>

You can add a converter that gets called when the data from the binding source arrives and before it gets delivered to the control. Here we have one condition when this debugging technique can't help: if the binding fails beforehand, the converter doesn't get called.

To implement the converter you have to derive a class from IValueConverter and implement it's methods:

   public class DatabindingDebugConverter : IValueConverter
public object Convert(object value, Type targetType,
object parameter, string language)
return value;
public object ConvertBack(object value, Type targetType,
object parameter, string language)
return value;

Then you have to declare the converter as a static resource in your page's xaml:

<local:DataBindingDebugConverter x:Key="DatabindingDebugConverter"/>

assuming you have declared the local namespace


in the page tag and call it in the data binding statement:

      <TextBlock Text="{Binding LineOne, Converter={StaticResource DataBindingDebugConverter}}" TextWrapping="Wrap" Style="{StaticResource PhoneTextExtraLargeStyle}"/>

Next you set a breakpoint in the Convert method and voilà, you can see the values that arrive from binding, if any.

Sample code

A sample project is in the works, please call again later...

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