MVC 3 Razor - Trigger validation from controller

I think what you are looking for is the RemoteAttribute.

This is a ValidationAttribute for remote validation. It works like the other validation attributes by adding model errors to your modelstate dictionary.

Check out these articles on using the RemoteAttribute:

• http://deanhume.com/Home/BlogPost/mvc-3-and-remote-validation/51
• http://davidhayden.com/blog/dave/archive/2011/01/04/ASPNETMVC3RemoteValidationTutorial.aspx

In controller: ModelState.AddModelError("ErrorEmail", "Error Message");

In View: @Html.ValidationMessage("ErrorEmail")

Hope this helps