context.AddObject(string EntitySetName, object entity) cannot find EntitySetName

Question

Hi,

I am trying to use "context.AddObject(string EntitySetName, object entity)" but I get an error saying that the EntitySetName could not be found. On investigating further I found that this was because the entity set name I was looking for was not present in the list of BaseEntitySets. How do I find the BaseEntitySet name from the DbSet name?

Ultimately I am simply trying to create a generic method to add an entity to a context without knowing the type of the DbSet at compile time. I can get the name of the DbSet (or even its type) but I cannot use DbSet<T> because T is unknown. I have this so far:

DbContext dBContext = Activator.CreateInstance(contextType);

ObjectContext = ((IObjectContextAdapter_dBContext).ObjectContext;

var entity = Activator.CreateInstance(entityType);

oBContext.AddObject("EntitySetName", entity);

but because the EntitySetName does not match the BaseEntitySet name the AddObject fails. The EntitySetName  does not match the BaseEntitySet name because the EntitySet is derived from another class, e.g.

Donor : Person

To complicate matters further EF then pluralizes "Person" to "People" for the BaseEntitySet. I switched off the pluralization convention but this only prevents pluralization of table names, not DbSet names.

Thanks

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Answer 1

Did you create code first or database first maps?

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JP Cowboy Coders Unite!

Answer 2

Hi, I am using code first.

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Answer 3

From a support perspective this is really beyond what we can do here in the forums. If you cannot determine your answer here or on your own, consider opening a support case with us. Visit this link to see the various support options that are available to better meet your needs:  http://support.microsoft.com/default.aspx?id=fh;en-us;offerprophone.

Answer 4

Hi, after quite a bit of investigation and testing I have come up with a method of digging up the information I needed:

            EntityContainer container = oBContext.MetadataWorkspace.GetEntityContainer
                                (oBContext.DefaultContainerName, DataSpace.CSpace);

            Dictionary<string, string> entityBaseNameBaseEntitySet =

                        (from e in container.BaseEntitySets
                         where e is EntitySet
                         select e).ToDictionary(e => e.ElementType.Name, e => e.Name);

            Dictionary<string, EntitySetAndTypeInfo> entitySetInfo =
                
                        (from p in t.GetProperties()
                         where p.PropertyType.IsGenericType &&
                         (p.PropertyType.GetGenericTypeDefinition() == typeof(DbSet<>) ||
                          p.PropertyType.GetGenericTypeDefinition() == typeof(IDbSet<>))
                         select new EntitySetAndTypeInfo()
                         {
                             EntitySetName = p.Name,
                             EntityType = p.PropertyType.GetGenericArguments().FirstOrDefault(),
                             EntityBaseType = FindEntityBase(p.PropertyType.GetGenericArguments().FirstOrDefault()),
                             BaseEntitySet =
                                (from c in container.BaseEntitySets
                                where c is EntitySet
                                where c.Name == FindEntityBase(p.PropertyType.GetGenericArguments().FirstOrDefault())
                                select c.ElementType.Name).FirstOrDefault()
                         }).ToDictionary(d => d.EntitySetName, d => d);

    public class EntitySetAndTypeInfo
    {
        public string EntitySetName { get; set; }
        public Type EntityType { get; set; }
        public string EntityBaseType { get; set; }
        public string BaseEntitySet { get; set; }
    }

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