DevForce supports INotifyDataErrorInfo and it works great to display errors that associated with certain fields. This part works great.

 

It doesn't work when I have form-level validation (entity level) and it doesn't work when I have validation level set to anything but error.

 

Solution is to create my own control to display all results but I need some kind of hook so I know when errors change..

Have you tried using VerifierBatchInterceptor?  http://drc.ideablade.com/xwiki/bin/view/Documentation/intercepting-a-verifier - http://drc.ideablade.com/xwiki/bin/view/Documentation/intercepting-a-verifier

 

I look at it but not sure how I integrate it. Do you have code sample?

 

I use Repositories to abstract EntityManager and data from my ViewModels. Ideally, I'd like to have repositories to raise event for me so I can use it in my VM. So, I need to know when specific instance of EntityManager does validation.

Here's the link for the code sample.  http://www.ideablade.com/friends/SimpleBatchInterceptorCodeSample.zip - www.ideablade.com/friends/SimpleBatchInterceptorCodeSample.zip

I'm taking an existing SL Validation code sample and adding a simple BatchInterceptor to it. Hopefully it can illustrate to you what it does. You can think of the BatchInterceptor as an event that is raised each time a validation (property level or entity level) is executed.

Basically what the sample does is load all employees and their respective orders onto a data grid. As soon as the employees are fetched, I'm calling 

_mgr.VerifierEngine.Execute(_employees[0]);

to execute an entity level validation on the first employee. Put your breakpoint under MyBatchInterceptor to see how the event is raised for each of the property's validation that gets executed.

Hope this helps.