Entity Framework querying by related entity

Question

I have 2 entities, Jobs and Appointments:

public class Job
{
    public int JobId { get; set; }
    public ICollection<Appointment> Appointments { get; set; }
}

public class Appointment
{
    [Key]
    public int AppointmentId { get; set; }

    [Required]
    public DateTime AppointmentDate { get; set; }

    [Required]
    [MaxLength(50)]
    public string Type { get; set; }

    public int Job_JobId { get; set; }

    [ForeignKey("Job_JobId")]
    public virtual Job Job { get; set; }
}

How do I return only jobs that have an "Initial" appointment type?

Something like the following (which isn't valid syntax):

jobs = jobs.Where(x => x.Appointments.Where(p => p.Type == "Initial"));

Answer 1

I believe you're looking for Any() to introduce the condition that a job must have at least one Appointment of type "Initial", viz:

var initialJobs = jobs
    .Where(j => j.Appointments.Any(a => a.Type == "Initial"));

Where requires a predicate argument (Func returning a bool), and Any() returns true if at least one element meets the inner predicate ( a.Type == "Initial" )

Answer 2

If you only want to load the appointments for jobs that have the type as Initial, you could also do this:

var jobs = appointments.Where(x => x.Type == "Initial").Select(x => x.Job);

This should give you Appointments inside the jobs that only have the Initial type.

Answer 3

If you wanna return list of jobs as long as the list contain at least one Type == "Initial" , you should use Any() , Your case seem looks like this

var jobs = jobs.Where(x => x.Appointments.Any(p => p.Type == "Initial"));

Or return job if it contains all appointments with Type == "Initial" , you might use Where()

var jobs = jobs.Where(x => 
{
   var appointmentCount = x.Appointments.Count();
   var validAppointments = x.Appointments.Where(p => p.Type == "Initial");

   return  appointmentCount  == validAppointments.Count();
});