Question

Here are my classes

public class Activity
{
    public int ID {get;set;}
    public string Personnel { get; set; }
    public Location Location { get; set; }
}

public class Location
{
    [Key]
    public string Name { get; set; }
}

When I save an Activity it creates a new Location, even if it already exists. How do I set it up so it uses existing Locations?

Answer 1

Load the existing Location through the context and use that as the property value of the Activity

eg:

using(var context = new MyDbContext())
{
   var location = context.Locations.FindByKey(/* set key*/);
   var activity = new Activity(){Personnel = "Foo", Location = location};
   context.Activities.Add(activity);
   context.SaveChanges();
}