EF Update DB启用迁移导航属性错误

我正在使用MVC 5的EF迁移-然而我得到我认为/认为是/是一个非常常见的错误，但我已经看到了常见的解决方案，我已经得到:

属性'companyId'不能配置为导航属性。该属性必须是有效的实体类型，并且该属性应该具有非抽象的getter和setter。对于集合属性，类型必须实现ICollection，其中T是有效的实体类型。

在enable-migrations和update-database之前，查看我的系统中的测试数据是否在我进行此更改之前被清除。在ASN模型中，我添加了testAsn的字符串属性，以查看是否将其作为列添加到数据库中。

我不确定这个错误是否与ASN或Contacts表/模型有关，但它们都具有相同的实现。

我是否误解了导航属性的使用?任何帮助都将非常感激。

[Table("Company")]
    public class Company
    {
        [Key]
        public int companyId { get; set; }
        [Required(ErrorMessage="Company name required.")]
        [StringLength(100)]
        public string name { get; set; }
        [Required(ErrorMessage = "Telephone required.")]
        public string telephone { get; set; }
        [Required(ErrorMessage="Registration Number required.")]
        [StringLength(30)]
        public string regNumber { get; set; }
        // navigation properties  of the models that belong to the company
        public virtual IList<Asn> asns { get; set; }
        public virtual IList<Contact> contacts { get; set; }
    }
[Table("Asn")]
    public class Asn
    {
        [Key]
        public int asnId { get; set; }
        public int companyId { get; set; }
        [ForeignKey("companyId")]
        // property I'm adding to test whether migrations is working
        public string testAsn { get; set; }
        // *******************************
        // as pointed out in the correct answer, the property below
        // this comment should be above testAsn
        // *******************************
        public virtual Company company { get; set; }
        [Required] // always has value
        public bool userBehalf { get; set; }
        [Required] // always has value
        public bool confirmAssignment { get; set; }
        [Required(ErrorMessage="Prefix required.")]
        public string prefixAnnounced { get; set; }
        [Required(ErrorMessage="Pending Ticket ID required.")]
        public string pendingTicket { get; set; }
        [DataType(DataType.MultilineText)]
        public string comments { get; set; }
        public bool asNumType { get; set; }
        public string reason { get; set; }
    }
    [Table("Contact")]
    public class Contact
    {
        [Key]
        public int contactId { get; set; }
        public int companyId { get; set; }
        [ForeignKey("companyId")]
        public virtual Company company { get; set; }
        [StringLength(100, MinimumLength=3)]
        [Required(ErrorMessage="Contact name required.")]
        public string name { get; set; }
        [Required(ErrorMessage="Telephone required.")]
        [StringLength(30, MinimumLength=11)]
        public string telephone { get; set; }
        [Required]
        [RegularExpression(@"^([a-zA-Z0-9_'-'.]+)@(('[[0-9]{1,3}" +
                            @"'.[0-9]{1,3}'.[0-9]{1,3}'.)|(([a-zA-Z0-9'-]+'" +
                            @".)+))([a-zA-Z]{2,4}|[0-9]{1,3})(']?)$",
                            ErrorMessage = "Email is not valid.")]
        public string email { get; set; }
        [Required(ErrorMessage = "Contact type required.")]
        public string type { get; set; }
    }