The property cannot be configured as a navigation property.

Question

I am trying to implement a domain model as follows:

This is an mvc framework application. The model code is as follows:

public class Login { [Key] public int LoginID { get; set; } public virtual Therapist Therapist { get; set; } public virtual Patient Patient { get; set; } } public class Patient { [Key] [ForeignKey("Login")] [Display(Name = "No.")] public int PatientId { get; set; } [ForeignKey("Therapist")] public int TherapistId { get; set; } [ForeignKey("Therapist")] public int TherapistId{ get; set; } public virtual Therapist Therapist { get; set; } public virtual Login Login { get; set; } } public class Therapist { [Key] [ForeignKey("Login")] [Display(Name = "No.")] public int TherapistId { get; set; } [ForeignKey("Login")] public int LoginId { get; set; } public virtual Login Login { get; set; } public virtual ICollection<Patient> Patients { get; set; } } 

I follow exactly what is in the training questions and, and no matter what I do, when I try to start the controller, I get the same error - Unable to retrieve metadata for 'Patient'. The property "TherapistId" cannot be configured as navigation property. The property must be a valid entity type and the property should have non-abstract getter and setter. For collection properties the type must implement ICollection<T> where T is a valid entity type Unable to retrieve metadata for 'Patient'. The property "TherapistId" cannot be configured as navigation property. The property must be a valid entity type and the property should have non-abstract getter and setter. For collection properties the type must implement ICollection<T> where T is a valid entity type Unable to retrieve metadata for 'Patient'. The property "TherapistId" cannot be configured as navigation property. The property must be a valid entity type and the property should have non-abstract getter and setter. For collection properties the type must implement ICollection<T> where T is a valid entity type . I don’t know what is wrong with TherapistId - maybe the whole idea of ​​the model is garbage?

Answer 1

I think your specific mistake in this case is that you have

 [ForeignKey("TherapistId")] public int? TherapistId { get; set; } 

instead

 [ForeignKey("Therapist")] public int? TherapistId { get; set; } 

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In any case, you seem to have a few problems, maybe something like this (I just saved the properties of the relations):

 public class Login { [Key] public int LoginID { get; set; } public virtual Therapist Therapist { get; set; } public virtual Patient Patient { get; set; } } public class Patient { [Key] [ForeignKey("Login")] [Display(Name = "No.")] public int PatientId { get; set; } public virtual Login Login { get; set; } // was this supposed to be optional? [ForeignKey("Therapist")] public int? TherapistId{ get; set; } public virtual Therapist Therapist { get; set; } } public class Therapist { [Key] [ForeignKey("Login")] [Display(Name = "No.")] public int TherapistId { get; set; } public virtual Login Login { get; set; } public virtual ICollection<Patient> Patients { get; set; } } 

Typically, for one-to-one relationships in EF, both sides of the relationship must have the same primary key.

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In fact, for what you are doing, perhaps you can try to use some kind of inheritance between Login , Patient and Therapist , because at the moment a Login can have both Patient and Therapist .