Check if field validation passed (isValid?)

Greetings,

I'm looking for a way to determine if a field is valid.  Is their some sort of boolean or function to determine whether or not a specific field (in its current state) passes the validation?

For example, lets say I have an Order, with a Line Item, and an Item Number.  If I want to find out whether the Item Number validation has passed (anywhere in my code), I want to be able to do something like:

if(Order.LineItem.ItemNumber.isValid == "True")

{

//do something

}

How can this be accomplished?

Thanks!!

GS