The entity type List`1 is not part of the model for the current context

Question

I've been using Database First, EF 4.1

I am getting "The entity type List`1 is not part of the model for the current context." error when trying to update a record from my Edit View.

The error is occurring at

db.Entry(properties).State = EntityState.Modified;

Here is my Model:

public class Users
     {
     [Key]
     public int User_ID { get; set; }
     public string UserName { get; set; }

     [NotMapped]
     public IEnumerable<App_Properties> User_Properties
     {
          get { return Properties.Where(u => u.User_ID == User_ID); }
     }

     public virtual ICollection<App_Properties> Properties { get; set; }
}

public class App_Properties
{
     [Key]
     public int Prop_ID { get; set; }
     public int User_ID { get; set; }
     public int App_ID { get; set; }
     public string Key { get; set; }
     public string Value { get; set; }
     public DateTime DateEntered { get; set; }
     public DateTime DateModified { get; set; }

     [ForeignKey("User_ID")]
     public virtual Users Users { get; set; }
}

Here is my Controller:

[HttpPost]
public ActionResult Edit(ICollection<App_Properties> properties)
{
     if (ModelState.IsValid)
     {
          foreach (var item in properties)
          {
               db.Entry(properties).State = EntityState.Modified;
          }

          db.SaveChanges();

          return RedirectToAction("Index");
     }

     return View(properties);
}

I suspect the foreach loop is not appropriate in setting the EntityState for each item in an ICollection.

Any assistance would be greatly appreciated.

Solution 1

Try changing your loop to:

foreach (var item in properties)
{
     db.Entry(item).State = EntityState.Modified;
}

You were calling db.Entry(properties), so you were trying to attach the whole collection at once. DbContext.Entry(object) expects a single object, not a collection.

Solution 2

Thanks, Leniency, for the answer. Worked great.

For what it's worth, I prefer to keep my EntityState.Modified assignments on a single line (as I have multiples) so used the following LINQ:

properties.ForEach(p => db.Entry(p).State = EntityState.Modified);

Comments

[Leniency]

A quick semantic note, the name App_Properties.Users would imply multiple users, not one. Convention tends to be that a single object has a singular name as saying var users = new Users() implies a collection of people, not a single item.

[Isaac Vallee]

Yeah, thanks... I have no control of the DB and I let the improper naming of the tables propagate down into my code.

[Leniency]

The db names don't have to though - it's very easy to change the mapping of your POCO to the actual database table OnModelCreating: modelBuilder.Entity<User>().ToTable("Users"). A simple F2 rename on the Users class will then propagate the rename across your project. Same with property names - you can custom map any of it. weblogs.asp.net/scottgu/archive/2010/07/23/…

[Isaac Vallee]

Thanks.. That got rid of that error but added a "Object with same key already exists in objectstatemanager error." I was able to get help with that error from stackoverflow.com/questions/8254854/….

[Rush.2707]

Thanks ... this was helpful

[Asad Naeem]

I got an idea from your answer so I did the following: I am using code first approach with LazyLoadingEnabled = false I had a collection of actions against a status so I loaded then like that dbContext.Entry(status).Collection(c=>c.Actions).Load();

[Asad Naeem]

It worked fine but issue arises when I found that there is an object which is related to each Action NextStatus so I used the following: foreach(var a in status.Actions) { dbContext.Entry(a).Reference(c=>c.nextStatsu).Load(); }