In WPF, we can update the underlying data model whenever the user makes any change to the data by leveraging UpdateSourceTrigger like this:
<TextBox Text="{Binding Path=TextProperty, UpdateSourceTrigger=PropertyChanged}"/>
In Window Phone UpdateSourceTrigger was not included in the XAML specification and to accomplish the same, a TextChanged handler was necessary like this:
(sender as TextBox).GetBindingExpression(TextBox.TextProperty).UpdateSource();
In Windows 8, I assumed that UpdateSourceTrigger would also be omitted – I was correct. I was surprised, however, to learn that GetBindingExpression() was also missing.
What is the best technique to accomplish, in Windows 8, what we accomplished in WPF with UpdateSourceTrigger and in Windows Phone with GetBindingExpression().UpdateSource()?
Please note: This question is for Windows 8 (Metro) development; this other question ( "UpdateSourceTrigger=PropertyChanged" equivalent for a Windows Phone 7 TextBox ) is for Windows Phone development – not to be confused.
As a matter of research, this example (which I created) uses a TextBox override to swap the text value between two properties causing the update. It is based on this. But, is there a better way? Something elegant?
It seems there is no
GetBindingExpressionor equivalent workaround. However you can extend the TextBox like this: https://mytoolkit.svn.codeplex.com/svn/WinRT/Controls/ExtendedTextBox.csStill this doesn’t solve the problem itself… (it’s really sad)
See also: