Web API, EF Code First and Duplicate Records - ef-code-first

Question

I am creating a REST service using Web API and am using EF Code First to retrieve and store data to back end that service. I have a bunch of classes defined and the EF creates the database no problems at all. I can retrieve the data and again have no issues. The problem I experience is when I try to write back a record. If I have created the following little mock up to reproduce the problem.
public class Company
{
[Key]
public int CompanyID { get; set; }
public string Name { get; set; }
}
public class Contact
{
[Key]
public int ContactID { get; set; }
public int CompanyID { get; set; }
public virtual Company Company { get; set; }
public string Name { get; set; }
}
public class Quote
{
[Key]
public int QuoteID { get; set; }
public int CustomerID { get; set; }
[ForeignKey("CustomerID")]
public virtual Company Customer { get; set; }
public int ContactID { get; set; }
public virtual Contact Contact { get; set; }
public string Reference { get; set; }
}
I then have three controllers in my REST service;
public class CompaniesController : ApiController
{
TestDBContext Context = new TestDBContext();
public IEnumerable<Company> GetCompanies()
{
return Context.Companies;
}
}
[Route("api/companies/{CompanyID}/contacts")]
public class CompanyContactsController : ApiController
{
TestDBContext Context = new TestDBContext();
public IEnumerable<Contact> GetCompanyContacts(int CompanyID)
{
return Context.Contacts.Where(C => C.CompanyID == CompanyID);
}
}
public class QuotesController : ApiController
{
TestDBContext Context = new TestDBContext();
public HttpResponseMessage PostQuote(Quote value)
{
try
{
if (ModelState.IsValid)
{
Context.Quotes.Add(value);
Context.SaveChanges();
// Return the object in the body.
HttpResponseMessage response = Request.CreateResponse(HttpStatusCode.OK, value);
response.Headers.Location = new Uri(Url.Link("DefaultApi", new { id = value.QuoteID }));
return response;
}
}
catch
{
}
return new HttpResponseMessage(HttpStatusCode.InternalServerError);
}
}
I pre-populate the database with a company and a contact and then have the following code to create a quote.
HttpClient Client = new HttpClient();
string CompanyURL = "http://localhost:56619/api/Companies";
string ContactURL = "http://localhost:56619/api/Companies/{0}/Contacts";
string QuoteURL = "http://localhost:56619/api/Quotes";
Client.GetAsync(CompanyURL).ContinueWith((T) =>
{
T.Result.EnsureSuccessStatusCode();
T.Result.Content.ReadAsAsync<IEnumerable<Company>>().ContinueWith((T2) =>
{
Company Comp = T2.Result.First();
Client.GetAsync(string.Format(ContactURL, Comp.CompanyID)).ContinueWith((T3) =>
{
T3.Result.EnsureSuccessStatusCode();
T3.Result.Content.ReadAsAsync<IEnumerable<Contact>>().ContinueWith((T4) =>
{
Contact Cont = T4.Result.First();
Quote Q = new Quote() { Customer = Comp, Contact = Cont, Reference = "Test" };
JsonMediaTypeFormatter Formatter = new JsonMediaTypeFormatter();
Formatter.SerializerSettings.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore;
Client.PostAsync<Quote>(QuoteURL, Q, Formatter).ContinueWith((T5) =>
{
T5.Result.EnsureSuccessStatusCode();
T5.Result.Content.ReadAsAsync<Quote>().ContinueWith((T6) =>
{
var Res = T6.Result;
});
});
});
});
});
});
I know the code is a little scrappy, but it is just thrown together to illustrate the problem without any extra stuff cluttering the code up.
When the EF saves the changes to the database it creates 1 quote, an extra contact and 2 extra company records. I'm puzzled as to why. I am using VS2013, EF6 and Web API 2.
If anyone has any suggestions they would be very gratefully be received.
Many thanks in advance,
Neil.