Data Validation on nested types in asp.net mvc3

I have following models.

public class RoleViewModel
{
    [DisplayName("Role Name")]
    [Required(ErrorMessage="Role Name is required.")]
    [WhiteSpaceAttribute(ErrorMessage="Name cannot contain white space")]
    [StringLength(25, ErrorMessage="Name cannot be be greater than 25 characters")]
    public string RoleName { get; set; }


    [StringLength(100, ErrorMessage = "Description should be less than 100 characters.")]
    public string Description { get; set; }

    [DefaultValue("")]
    public string DisplayMessage { get; set; }


    public bool IsSuccess { get; set; }
}

and

public class RoleDetailsModel
{
    public RoleViewModel RoleViewModel { get; set; }

    public IList<RoleResourceModel> RoleResources { get; set; }
}

Here, when I am using the RoleViewModel while creating a role, all the validations are executed as expected. However when I use the RoleDetailsModel (for edit), none of the validations are executed.

From here it开发者_运维问答 seems that validations are not executed for nested types. Please let me know if my understanding is correct.

If this is the case, How do I implement the above case? Simple way is to add the same validation in RoleDetailsModel. But this will violate the DRY (Don't Repeat Yourself).

UPDATE: Actually I had missed the ModelState.IsValid code in controller. I have added that and now it is working fine on server side.

Thanks for clearing my understanding on the nested types part.