Q:

Interface of virtual collection

Is there any possibility to create an interface in order to require a virtual collection type in my class? 
Regards
namespace Models. Entities
{

    public partial class FileType : IMyInterface
    {
        public long CompanyId { get; set; }
        public long FileTypeId { get; set; }
        public string AcceptType { get; set; }

        //IMyInterface contract
        public virtual ICollection<Translation> FileTypeTranslations { get; set; }

        public FileType()
        {
            this. FileTypeTranslations = new HashSet<FileTypeTranslation>();
        }
    }

    public class Translation : EntityTranslation<long, FileType>
    {
        [Required]
        public string TypeName { get; set; }
    }
}

A:

No.  virtual is an implementation detail not a contract (ie.  interface) detail. 

The virtual keyword is used to modify a method, property, indexer, or event declaration and allow for it to be overridden in a derived class. 

I marked the key part of that description from the documentation in bold

