Wpf binding not updating propertychanged
The first two has already been described, while the last one simply means that the update has to be pushed manually through to occur, using a call to Update Source on the Binding.
As you can see, each of the three textboxes now uses a different Update Source Trigger.
Instead, the source was updated only after focus was lost on the Text Box.
This behavior is controlled by a property on the binding called Update Source Trigger.
Yesterday I was working on a small prototype, which I will be blogging about shortly, and ran across the common problem of my bindings not updating.
A very common problem, and one that’s usually a very simple fix once you’ve tracked it down.
As of writing, all properties except for the Text property, is updated as soon as the property changes (Property Changed), while the Text property is updated when focus on the destination element is lost (Lost Focus).
I threw in a few breakpoints and I could see my View Model was changing, I could see the On Property Changed method being hit, but there didn’t seem to be any listeners and as a result my UI was just ignoring the changes.
After a few minutes of head scratching I noticed that although my class was firing the Property Changed event correctly, I hadn’t added INotify Property Changed to my class declaration when I removed the base class!
So, based on the change in first name and last name, we have to automatically update the full name.
In the previous article we saw how changes in a Text Box was not immediately sent back to the source.