I am working on an App that uses popups for add forms (this can't be changed).
When an add form is submitted jQuery captures the submit, and does an Ajax post to the server. There is custom validation on the ViewModel that is called when the submit happens. If there is an error, I need to return the rendered partial with the errors shown in the validation summary.
I have tried various approaches including returning the partial view and replacing the modal dialog (this gets me close).
If there is no errors then we would need to do an action (hide a model dialog).