Question

How I can delete an entity using EF5? I’m getting this error:

The object cannot be deleted because it was not found in the ObjectStateManager.

when I try to call .Remove on my DbSet. After googling I tried that

mycontext.Attach(entity)
mycontext.Remove(entity)

But in this way I get:

An object with the same key already exists in the ObjectStateManager. The ObjectStateManager cannot track multiple objects with the same key.

So, is it or not in ObjectStateManager?! 🙂

My entity is like that:

[Table("Words")]
public class Word : IWord
{
    [Key, Required]
    public int WordId { get; set; }

    [Required, StringLength(50)]
    public string Tag { get; set; }

    //Foreign Key
    public int VocabularyId { get; set; }

    //Navigation
    public virtual Vocabulary Vocabulary { get; set; }
    public virtual Language Language { get; set; }
    public virtual List<Translation> Translations { get; set; }

}

Answer 1

You can consider 2 scenario:

1. Connected scenario: you load the entity from database and mark it as deleted

var word = ctx.Words.Where(a=>a.WordId == wordId).First();
ctx.DeleteObject(word);
ctx.SaveChanges();

2. Disconnected scenario: attach an existing entity and mark it as deleted

var word = new Word() { WordId = id };
ctx.Words.Attach(word);
ctx.DeleteObject(word);
ctx.SaveChanges();

The second approach will help you avoid un-necessary database round trip