Entity Framework - Code First - Update won't change Foreign Key - entity-framework

Question

I just can't find any code that changes the foreign key. How do I tell the context that the foreign key has changed so that it updates the database? I have been attempting to get this to work for 2 months now:
These are the models:
namespace MyApp.WebApi.Models
{
public class Project
{
public int ProjectId { get; set; }
public string Description { get; set; }
public string Name { get; set; }
// Foreign Key - Project Status
public virtual ProjectStatus ProjectStatus { get; set; }
}
public class ProjectStatus
{
public int ProjectStatusId { get; set; }
public string Name { get; set; }
}
public class HerculesWebApiContext : DbContext
{
public HerculesWebApiContext() : base("name=HerculesWebApiContext") { }
public DbSet<Project> Projects { get; set; }
public DbSet<ProjectStatus> ProjectStatuses { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder) { }
}
}
This is the controller for the Web API:
namespace MyApp.WebApi.Controllers
{
public class ProjectController : ApiController
{
private HerculesWebApiContext db = new HerculesWebApiContext();
public void PutProject(int id, [FromBody]Project project)
{
if (!ModelState.IsValid) throw new HttpResponseException(HttpStatusCode.BadRequest);
if (id != project.ProjectId) throw new HttpResponseException(HttpStatusCode.BadRequest);
// I need some code here to tell EF that the FK has changed
db.Entry(project).State = EntityState.Modified;
// Try catch around this
db.SaveChanges();
}
The above code will not update the Project Status Foreign Key even if it has changed in the JSON object that is passed to the function. The object is returned in the same format that the Web API provided it but with the Project Status object updated:
[{"ProjectStatus":{"ProjectStatusId":2,"Name":"Started"},"ProjectId":3,"Description":"test description","Name":"test project"}]
I have tried:
db.Projects.Attach(db.Projects.Single(c => c.ProjectId == project.ProjectId));
((IObjectContextAdapter)db).ObjectContext
.ApplyCurrentValues("Projects", project);
I have also tried:
db.Entry(project.ProjectStatus).CurrentValues.SetValues(new ProjectStatus { ProjectStatusId = project.ProjectStatus.ProjectStatusId });
I have also tried this:
var per = new ProjectStatus { ProjectStatusId = project.ProjectStatus.ProjectStatusId }; // create the stub
db.ProjectStatuses.Attach(per);
db.Entry(project.ProjectStatus).CurrentValues.SetValues(per);
These are the table T-SQL files that are automatically created from my models:
Projects Table:
CREATE TABLE [dbo].[Projects] (
[ProjectId] INT IDENTITY (1, 1) NOT NULL,
[Description] NVARCHAR (MAX) NULL,
[Name] NVARCHAR (MAX) NULL,
[ProjectStatus_ProjectStatusId] INT NOT NULL,
CONSTRAINT [PK_dbo.Projects] PRIMARY KEY CLUSTERED ([ProjectId] ASC),
CONSTRAINT [FK_dbo.Projects_dbo.ProjectStatus_ProjectStatusId] FOREIGN KEY ([ProjectStatus_ProjectStatusId]) REFERENCES [dbo].[ProjectStatus] ([ProjectStatusId]) ON DELETE CASCADE
Project Statuses Table
CREATE TABLE [dbo].[ProjectStatus] (
[ProjectStatusId] INT IDENTITY (1, 1) NOT NULL,
[Name] NVARCHAR (MAX) NULL,
CONSTRAINT [PK_dbo.ProjectStatus] PRIMARY KEY CLUSTERED ([ProjectStatusId] ASC)
);

Answer 1

You need to do two things. First explicitly state your primary keys for each class.
Add the [Key] attribute to
Project class, above the line public int ProjectId { get; set; }
ProjectStatus class, above the line public int ProjectStatusId { get; set; }
Secondly add the property for your foreign key to your Project class. Add this line:
public int ProjectStatusId { get; set; }