Animate WPF Text when binding updates, how?

wpf data-binding animation effects
HiteshP picture HiteshP · Jul 22, 2009 · Viewed 8.2k times · Source

I want to be able to create a fade animation on a text element when the binding to that element updates. In other words, the effect is that as text gets added to a text box one sees a fading effect as the text updates and then fades out. I do'nt know how to achieve this. I have seen something similar using an EventTrigger on a RoutedEvent such as FrameworkElement.Loaded but how does one detect when a binding updates?

Thanks.

Answer

Charlie picture Charlie · Jul 22, 2009

You can set properties on your binding that will cause events to be fired. There are two properties available:

  1. NotifyOnSourceUpdated: Raise the SourceUpdated event when a value is transferred from the binding target to the binding source.
  2. NotifyOnTargetUpdated: Raise the TargetUpdated event when a value is transferred from the binding source to the binding target.

From the description of your setup, it sounds like you want to use NotifyOnTargetUpdated. Set that to true in your binding, then whenever the target updates, the Binding.TargetUpdated event will fire. You can then listen to that event in an EventTrigger, and fade your text.

Related questions

WPF animation: binding to the "To" attribute of storyboard animation

I'm trying to create a button that behaves similarly to the "slide" button on the iPhone. I have an animation that adjusts the position and width of the button, but I want these values to be based on the text …

Read More
Binding a WPF ComboBox to a custom list

I have a ComboBox that doesn't seem to update the SelectedItem/SelectedValue. The ComboBox ItemsSource is bound to a property on a ViewModel class that lists a bunch of RAS phonebook entries as a CollectionView. Then I've bound (at separate …

Read More
How do I use WPF bindings with RelativeSource?

How do I use RelativeSource with WPF bindings and what are the different use-cases?

Read More