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

Question

I am getting this error \"The object cannot be deleted because it was not found in the ObjectStateManager.\"

My code is:

    protected MyEntities sql         


        

Answer 1

Just to propergate on Kjartans explanation:

I had:

public Project DeleteProject(int id)
    {
        using (var context = new Context())
        {
            var p = GetProject(id);
            context.Projects.Remove(p);
            context.SaveChanges();
            return p;
        }
    }

The problem is that I used my own method (GetProject()) to get the entity (hence using another context to load the entity):

public Project GetProject(int id)
    {
        using (var context = new Context())
        {
            var project = context.Projects
                .Include(p => p.Reports.Select(q => q.Issues.Select(r => r.Profession)))
                .Include(p => p.Reports.Select(q => q.Issues.Select(r => r.Room)))
                .SingleOrDefault(x => x.Id == id);
            return project;      
        }
    }

One solution could be to attach the loaded entity as Kjartan states, another could be mine solution, to load the entity within the same context:

public Project DeleteProject(int id)
    {
        using (var context = new Context())
        {
            var p = context.Projects.SingleOrDefault(x => x.Id == id);
            if (p == null)
                return p;

            context.Projects.Remove(p);
            context.SaveChanges();
            return p;
        }
    }