I have two types of entities: an employee entity and an office entity, with a one to many relationship between the two such that there are many employees for one office. For EF, a DbSet is created in the context file for each entity:
public DbSet<Office> Offices { get; set; }
public DbSet<Employee> Employees { get; set; }
An EF tutorial that I did had me do my CRUD methods for a specific entity. For example, the method below creates an office and adds it to the office DbSet (ignore the MVC stuff -- I am not doing that anymore):
public ActionResult Create([Bind(Include = "Address,BusinessName")] Office office)
{
try
{
if (ModelState.IsValid)
{
db.Offices.Add(office);
db.SaveChanges();
return RedirectToAction("Index");
}
}
catch (DataException /* dex */)
{
//Log the error (uncomment dex variable name and add a line here to write a log.
ModelState.AddModelError("", "Unable to save changes. Try again, and if the problem persists see your system administrator.");
}
return View(office);
}
Basically the two things I want to emphasize is that an Office object is passed into the method, and that the office is added to the Office DbSet by explicitly writing db.Offices:
db.Offices.Add(office);
However, I need to write a method in which a generic entity object can be passed in, and I can add this to its correct DbSet. The rough idea for the method I have is something like this (I have ignored all the MVC stuff):
public void Create(object entityToCreate)
{
db.CorrespondingEntityType.Add(entityToCreate);
db.SaveChanges();
}
So let's say I have an Employee object. I can pass this Employee into the Create method and it can see that this is an Employee, and so it would add it to the Employees DbSet. I don't know if EF supports this though. An alternative would be to make a switch statement and that way depending on the type of the entity being passed in, I could directly call which DbSet to add the entity to. But I want to avoid that because I will be working with a lot more entities than just these two. Also I will be having to do similar things for the other CRUD methods.
I saw this documentation from msdn about the ObjectSet.AddObject Method, and it seems like it should be useful, but I'm not sure how it works.
See Question&Answers more detail:
os 与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…