Question

[Everything stripped down to highlight the problem]

SchemeRequest
------------------------------
Id
SchemeId [FK to Schemes Table]
------------------------------

using(var scope = new TransactionScope())
{
    var request = new SchemeRequest { SchemeId = [schemeId] };
    this.dbContext.SchemeRequests.Add(request);
    this.dbContext.SaveChanges();

    this.mailer.SendMail(request); // request.Scheme is null when it should not be

    scope.Complete();
}

I am using EF Model first. Now after the call to SaveChanges the Navigation property Scheme in SchemeRequest is null. I am not sure why. Can anyone help? There is another navigation property which seems to work fine. How do I debug this ie how do I find out whats happening behind the scenes.?

I checked and doublechecked the relationships, properties etc but everything seems to be ok.

Answer 1

It’s not expected that the navigation property is loaded. You only save a new entitiy without setting its navigation property. EF does not load another entity automatically when you save the parent.

However, the navigation property would be set in two situations:

• The Scheme with the SchemeId you set in the new SchemeRequest is already loaded and attached to the context. EF would fix the relationship automatically and set the navigation property.

• If you use lazy loading the navigation property would be loaded after setting the SchemeId as soon as you access it. However, you need to create the new SchemeRequest as a lazy loading proxy instead of using new:

  var request = this.dbContext.SchemeRequests.Create();
  request.SchemeId = schemeId;