Entity Framework many to many table insert complex relations - entity-framework

Question

This is my simplified schema.
I want to add a contact who is a custodian and attach them to an existing facility. The ContactType just states what type of contact the record is such as a company or individual. In this case the custodian is an individual.
I can insert a contact by itself just fine.
The complication for me is because of the many to many and one to many relationships.
In the controller I have
vm.Contact.Facilities.Add(new Facility { FacilityID = vm.SelectedFacilityID });
_repo.SaveContact(vm);
In the repo
_db.Contacts.Add(vm.Contact);
_db.SaveChanges();
This gives me a foreign key error since it tries to insert a new facility and I have other foreign keys in that table not shown. I don't want to add a facility but just reference the FacilityID.
Convention is to Not explicitly try to insert a record in the many to many, FacilityCustodian table directly by doing something like this
var fc = new FacilityCustodian { CustodianFacilityID = vm.SelectedFacilityID };
vm.Contact.FacilityCustodian.Add(fc);
I also tried
foreach (var facility in vm.Contact.Facilities)
{
_db.Entry(facility).State = EntityState.Unchanged;
}
Most of the examples I have seen don't have both relationships so I'm not sure how to proceed.
Thanks for any help.
ADDED CODE
using Licensing.Models;
namespace Licensing
{
using System.Data.Entity;
public class Context : DbContext
{
public Context()
: base("name=Context")
{
}
public virtual DbSet<Contact> Contacts { get; set; }
public virtual DbSet<ContactType> ContactTypes { get; set; }
public virtual DbSet<Facility> Facilities { get; set; }
public virtual DbSet<FacilityCandler> FacilityCustodians { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Contact>()
.Property(e => e.FName)
.IsUnicode(false);
modelBuilder.Entity<Contact>()
.Property(e => e.LName)
.IsUnicode(false);
modelBuilder.Entity<Contact>()
.HasMany(e => e.Facilities)
.WithRequired(e => e.Contact)
.WillCascadeOnDelete(false);
modelBuilder.Entity<Contact>()
.HasMany(e => e.FacilityCustodians)
.WithRequired(e => e.Contact)
.HasForeignKey(e => e.CustodianFacilityID)
.WillCascadeOnDelete(false);
modelBuilder.Entity<ContactType>()
.Property(e => e.Type)
.IsUnicode(false);
modelBuilder.Entity<ContactType>()
.HasMany(e => e.Contacts)
.WithRequired(e => e.ContactType)
.WillCascadeOnDelete(false);
modelBuilder.Entity<Facility>()
.HasMany(e => e.FacilityCustodians)
.WithRequired(e => e.Facility)
.HasForeignKey(e => e.CustodianFacilityID)
.WillCascadeOnDelete(false);
}
}
}
namespace Licensing.Models
{
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using System.Data.Entity.Spatial;
[Table("Contact")]
public class Contact
{
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2214:DoNotCallOverridableMethodsInConstructors")]
public Contact()
{
Facilities = new HashSet<Facility>();
FacilityCustodians = new HashSet<FacilityCustodian>();
}
[Key]
public int ContactID { get; set; }
public int ContactTypeID { get; set; }
[Display(Name = "First Name")]
[RegularExpression(#"^[a-zA-Z'.\s]+$", ErrorMessage = "Enter a valid Name")]
[StringLength(150)]
public string FName { get; set; }
[Display(Name = "Last Name")]
[RegularExpression(#"^[a-zA-Z'\s]+$", ErrorMessage = "Enter a valid Name")]
[StringLength(150)]
public string LName { get; set; }
public virtual ContactType ContactType { get; set; }
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly")]
public virtual ICollection<Facility> Facilities { get; set; }
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly")]
public virtual ICollection<FacilityCustodian> FacilityCustodians { get; set; }
}
}
using System.ComponentModel.DataAnnotations;
namespace Licensing.Models
{
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations.Schema;
[Table("Facility")]
public class Facility
{
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2214:DoNotCallOverridableMethodsInConstructors")]
public Facility()
{
FacilityCustodians = new HashSet<FacilityCustodian>();
}
[Key]
public int FacilityID { get; set; }
public int ContactID { get; set; }
public virtual Contact Contact { get; set; }
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly")]
public virtual ICollection<FacilityCustodian> FacilityCustodians { get; set; }
}
}
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
namespace Licensing.Models
{
[Table("FacilityCustodian")]
public partial class FacilityCustodian
{
[Key]
[Column(Order = 0)]
[DatabaseGenerated(DatabaseGeneratedOption.None)]
public int CustodianFacilityID { get; set; }
[Key]
[Column(Order = 1)]
[DatabaseGenerated(DatabaseGeneratedOption.None)]
public int CustodianContactID { get; set; }
public virtual Contact Contact { get; set; }
public virtual Facility Facility { get; set; }
}
}
namespace Licensing.Models
{
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
[Table("ContactType")]
public class ContactType
{
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2214:DoNotCallOverridableMethodsInConstructors")]
public ContactType()
{
Contacts = new HashSet<Contact>();
}
[DatabaseGenerated(DatabaseGeneratedOption.None)]
public int ContactTypeID { get; set; }
[Required]
[StringLength(10)]
public string Type { get; set; }
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly")]
public virtual ICollection<Contact> Contacts { get; set; }
}
}
UPDATE Working Code
var existingFacility = _repo.GetFacilityByFacilityID(vm.SelectedFacilityID);
vm.Contact.LName = vm.LName;
vm.Contact.FName = vm.FName;
vm.Contact.Name = vm.FName + " " + vm.LName;
vm.Contact.ContactTypeID = 1;
vm.Contact.FacilityCustodians.Add(existingFacility);
_db.Contacts.Add(vm.Contact);
_db.SaveChanges();

Answer 1

Try this Since I dont have complete folder I tried to simplify the model all classes are name mentioned in diagram but I create. Below are my model classes . The import thing to note is that read the entoty from contecxt first and then updated the values and set entitystate accordingly . This will solve your issue .
Model classes :-
public class ContactType
{
public int ContactTypeId { get; set; }
public string Name { get; set; }
}
public class Contact
{
public int ContactId { get; set; }
public string Name { get; set; }
public int ContactTypeId { get; set; }
[ForeignKey("ContactTypeId")]
public virtual ContactType ContactType { get; set; }
public virtual ICollection<Facility> Facilities { get; set; }
}
public class FacilityCustodian
{
public int FacilityId { get; set; }
public int ContactTypeId { get; set; }
[ForeignKey("ContactId")]
public virtual Contact Contact { get; set; }
[ForeignKey("FacilityId")]
public virtual
Facility Facility { get; set; }
}
public class Facility
{
public int FacilityId { get; set; }
public string Location { get; set; }
public int ContactId { get; set; }
[ForeignKey("ContactId")]
public virtual Contact Contact { get; set; }
public virtual ICollection<Contact> Contacts { get; set; }
}
-- here I am showing you to update existing contact and add a new facility to it . same as you case you want to update facility ...
using (var ctx = new SampleDbContext())
{
//this is important to read the entity first .
var contact = ctx.Contacts.FirstOrDefault(x=>x.ContactId ==vm.Contact.ContactId);
if (contact != null)
{
// Since facilityId is a primary key I set it to autoincrement so I dont have to set it .You can set if it is not primarykey
contact.Name = "Updated";
// update the entity and add new information inthis i am adding facility
var facility = new Facility
{
Location = "LocA",
// assiging same entity to facility so that it will not treat it as a new contact
Contact = contact
};
contact.Facilities.Add(facility);
// Finaly update the state of the entity .
ctx.Entry(contact).State = EntityState.Modified;
ctx.SaveChanges();
}
}
After this it will not insert new contact when you save in . In my example I choose to add new facility but keep contact same . You can do same with facility but the concept is same . First read the object from EF coontext update values which you need to update and set state to Modified . This will tell that all other Entities in graph are same expect which you modified.
SQL Profiler Query to make sure Update happn for Contact and insert for facility
exec sp_executesql N'UPDATE [dbo].[Contacts]
SET [Name] = #0, [ContactTypeId] = #1
WHERE ([ContactId] = #2)
',N'#0 nvarchar(max) ,#1 int,#2 int',#0=N'Updated',#1=1,#2=1
go
exec sp_executesql N'INSERT [dbo].[Facilities]([Location], [ContactId], [Contact_ContactId])
VALUES (#0, #1, #2)
SELECT [FacilityId]
FROM [dbo].[Facilities]
WHERE ##ROWCOUNT > 0 AND [FacilityId] = scope_identity()',N'#0nvarchar(max) ,#1 int,#2 int',#0=N'LocA',#1=1,#2=1
go