ASP.net MVC 4 尝试删除记录时出错

Question

I'm trying to delete a client record. The client contains an address and I guess I'm having issues with the order of deletion when it comes to their relationship. Basically I want to delete a client and if they have an address, to delete that along with it. This is the complete exception error message I get:

DbUpdateException was unhandled by user code

An error occurred while saving entities that do not expose foreign key properties for their relationships. The EntityEntries property will return null because a single entity cannot be identified as the source of the exception. Handling of exceptions while saving can be made easier by exposing foreign key properties in your entity types. See the InnerException for details.

Models

public class Address
{
    [Required]
    public int Id { get; set; }

    [DataType(DataType.Text)]
    [Display(Name = "Street Address")]
    public string StreetAddress { get; set; }

    [DataType(DataType.Text)]
    [Display(Name = "Postal Code")]
    public string PostalCode { get; set; }

    [DataType(DataType.Text)]
    public string City {get; set; }

    [DataType(DataType.Text)]
    public string Province {get; set;}

    public virtual Clients client { get; set; }

}
public class Clients
{
    [Required]
    public long Id { get; set; }

    [Required]
    [DataType(DataType.Text)]
    [Display(Name = "First Name")]
    public string FirstName { get; set; }

    [Required]
    [DataType(DataType.Text)]
    [Display(Name = "Last Name")]
    public string LastName { get; set; }

    [Required]
    [DataType(DataType.PhoneNumber)]
    [Display(Name = "Phone ")]
    public string PhoneNumber { get; set; }

    public virtual Address Address {get; set;}

    [Display(Name = "Email List")]
    public Boolean EmailList { get; set; }

    [DataType(DataType.EmailAddress)]
    [Display(Name = "E-mail")]
    public string Email { get; set; }

    [DataType(DataType.Text)]
    [Display(Name = "Hair Type")]
    public string HairType { get; set; }        

   [DataType(DataType.MultilineText)]
    public string Description { get; set; }
}

Context Class

public class VolumeV2Context : DbContext
{
    public DbSet<GiftCard> GiftCards { get; set; }
    public DbSet<Clients> Clients { get; set; }
    public DbSet<Address> Address { get; set; }
    public DbSet<Inventory> Inventories { get; set; }  


    protected override void OnModelCreating(System.Data.Entity.DbModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Clients>()
            .HasOptional(j => j.Address)
            .WithOptionalDependent()
            .WillCascadeOnDelete(true);

       /* modelBuilder.Entity<Address>()
            .HasRequired(j => j.client)
            .WithRequiredDependent()
            .WillCascadeOnDelete(true) ;                           
        */


        base.OnModelCreating(modelBuilder);
    }
}

Client Controller Delete Method

[HttpPost, ActionName("Delete")]
    public ActionResult DeleteConfirmed(long id)
    {
        //find the client
        Clients clients = db.Clients.Find(id);

        //find the address
        Address address = db.Address.Find(clients.Address.Id);

        //  set the reference to null?
        address.client = null;                       

        //remove the address foreign key?
         clients.Address = null;

        //Apply to db?
         db.Entry(address).CurrentValues.SetValues(address);
         db.Entry(clients).CurrentValues.SetValues(clients);

        db.Address.Remove(address);

        //remove the client
        db.Clients.Remove(clients);
        //exception error happens here 
        db.SaveChanges();
        return RedirectToAction("Index");
    }

Is there something wrong with my order or deletion ? or am I just not doing something right? I just want to have the ability to remove clients with or without an address.

Answer 1

Remove the reference from an address to a client. Just keep your reference from a client to an address, that will do.