I have validation set up on the cells and it works as expected (placing a red highlight around the textbox and adding a tooltip with the error). However, If I try to access
You might run into problems with virtualization with this but you probably do have to look at the containers:
var errors = (from c in
(from object i in _myGrid.ItemsSource
select _myGrid.ItemContainerGenerator.ContainerFromItem(i))
where c != null
select Validation.GetHasError(c))
.FirstOrDefault(x => x);
if (errors)
{
//There be errors
}