Validation in asp.net MVC - validation only to happen when "asked"

I've got a slightly different validation requirement than the usual "when save, validate!". The system can allow someone to update a bunch of times without being "bothered" with a validation listing UNTIL they say it's complete. I thought I might be able 开发者_如何学Goto pull a fast one and put the [HandleError] on the method of which this would fire, but that validates every save.

Is there an attribte I can put into my custom validator that can handle this or am I going to have to write up my own HandleError attribute?