How to make ICollection<Child Entities> Required. How - entity-framework-4.1

Question

Here is my Master Entity who will contains a list of Language
public partial class WebSite
{
public WebSite()
{
this.WebSiteLanguages = new HashSet<WebSiteLanguage>();
}
public int Id { get; set; }
public Nullable<int> WLUserID { get; set; }
public string DomainName { get; set; }
public Nullable<bool> IsActive { get; set; }
//[Required]
public virtual ICollection<WebSiteLanguage> WebSiteLanguages { get; set; }
}
My WebSiteLanguage Child class is
public partial class WebSiteLanguage
{
public int Id { get; set; }
public string LanguageName { get; set; }
public Nullable<int> WebSiteID { get; set; }
public bool IsDefault { get; set; }
public virtual WebSite WebSite { get; set; }
}
In my View, I can Add many language as I want within an ajax call.
My Question is :
Is it possible to make the
public virtual ICollection WebSiteLanguages { get;
set; }
Required. The Website Entity is not valid if there is no WebSiteLanguage created.
Thanks a lot.

Answer 1

As per post http://blogs.msdn.com/b/adonet/archive/2011/05/27/ef-4-1-validation.aspx navigation properties are excluded from facet validation "as you could set the associated FK value and the navigation property would be set on SaveChanges()". To validate that a navigation property is not null you can:
create a custom attribute that validates it (be it on the type or on the property)
implement IValidatableObject interface that does the above
override DbContext.ValidateEntity protected method so that it validates that the property is not null and if this is the case calls base.ValidateEntity() to validate other properties (see this for more details: http://blogs.msdn.com/b/adonet/archive/2010/12/15/ef-feature-ctp5-validation.aspx)
The 3rd solution seems to be the cleanest.