Question

In another question, I asked how you could show errors for non-editor controls in an Infragistics XamGrid. Yet another question addresses the main issue of what I am trying to do: show errors in response to server-side validation.

Going even more general, has anyone come up with a pattern that works well for visualizing errors in Silverlight that does not use IDataErrorInfo or INotifyDataErrorInfo mechanisms? Back in my winform days I came up with something because validation seemed almost an afterthought. Now though MVVM suggests binding views (e.g. control styles, backgrounds, tooltips, and such) to view model “error” properties, but in practice it seems that the two above interfaces are predominate, and technology-specific (yes I’m aware the pattern and WPF/Silverlight coincided).

Is there something other than the above mechanism that is viable in an MVVM design? What other alternatives are there? At the end of the day though, I’m looking for a Silverlight solution that fits with MVVM, but that works a bit more generally than INotifyDataErrorInfo because not all controls (especially third-party ones) seem to support this, or if they do, not exactly in the way expected.

Answer 1

In the XamGrid case, I implemented INotifyDataErrorInfo as in “the pattern”, but instead of listening for notifications, I just checked the backing error collection in a conditional cell formatter.