Question

I’m getting there with this WPF validation, IDataErrorInfo, INotifyPropertyChange stuff, but new issue on refresh. I have a window with a bunch of controls on it. I have a tabbed page interface and for simplicity have 2 pages… 5 controls on each.

I start to “Add” a record, so all fields are blank. Ex: 3 of the fields on the first page that require validation are properly flagged as red border to indicate they are required… no problem.

Now, I click on to page 2 and immediately back to page 1. The red borders are all gone. They don’t reappear red unless I explicitly tab through them to re-focus them, lose focus and force it to do its lostfocus / property changed validation via IDataErrorInfo.

First, any explanation WHY WPF is losing what the first page looks like just because it has to change page 1’s visiblity to show page 2, and then back to page 1.

Second, suggestions on how to force the controls to be properly refreshed with the red border indicating they are required.

Thanks

Answer 1

If I recall correctly, the default error validation markers for controls are just red boxes overlaid over the top of the control, not part of the control itself, so the visibility of that overlay does not persist if the control is hidden. You might try changing the control template to incorporate a red border / label directly as part of the control, and that issue might be cleared up.

To force all your bindings to refresh (and therefore their validation) all you need to do is call RaisePropertyChanged again for any property you want to re-validate. It’s a little wasteful, but you can just call RaisePropertyChanged with an empty string as parameter, and it will raise for all properties in the viewmodel.