Question

I have some issues with date comparisons I’m working on that you will see in the code (how to do DateTime.Now.AddMonth(2) without a compile error would be nice to know), but what I’m really interested in is why when I iterate through my foreach, and attempt to print the employer organization name, I get a null pointer exception. Following debug confirms that the employer entity is present, but null. I expected that join would have given me access to this…

 csoDBConDataContext db = new csoDBConDataContext();
 db.ObjectTrackingEnabled = false;//see above comment

 var results = (from job in db.jobs
                join employer in db.employers on job.employer_id equals 
                     employer.employer_id
                where job.cache_major.Contains("business") && 
                      job.count_major <= 30 && job.del != true &&
                      job.joblocation != null &&
                      DateTime.Now.AddMonth(2).CompareTo(((DateTime)job.postdate)) >= 0 &&
                      DateTime.Now.CompareTo(((DateTime)job.expiredate)) >= 0 &&
                      job.status_id != 406
                 orderby Convert.ToDateTime(job.postdate).DayOfYear
                 select job
                ).Take(20);

 foreach (var j in results) {
          output += j.jobtitle + j.joblocation + j.expiredate + j.postdate +
          j.employer.organizationname + Environment.NewLine + Environment.NewLine;
         }

Answer 1

By selecting job, you are effectively telling Entity Framework that you are only interested in the scalar values on the Job type.

You can eager load employer properties like this:

var results = (from job in db.jobs.Include("employer")
              // ...