I have been looking at the links regarding the concurrency issues – but I do not know what I am supposed to do J

I am debugging the application up against a database that is only used by me – so there should not be any concurrency problems.

I have done something similar as described above, but where the many-to-many relations are in a table that has a “payload” and therefore exists as a type in my entity model. This works fine.

Here is my code for the add and remove methods, which work fine:

        protected void OnRemoveGroup(EntPointGroupAccess newValue)

        {

            newValue.EntityAspect.Delete();

            p_groupsWithAccess = null;

        }

        protected void OnAddGroup(EntUser newValue)

        {

            var tmp = C2NetDomainModelEntityManager.DefaultManager.CreateEntity<EntPointGroupAccess>();

            tmp.p_userID = newValue.p_userID;

            tmp.p_customerID = m_pointGroup.p_customerID;

            tmp.p_pointGrID = m_pointGroup.p_pointGrID;

            tmp.p_readWrite = 3;

            tmp.EntityAspect.AddToManager();

            p_groupsWithAccess = null;

        }

I am now thinking of making the table that contains the many-to-many relations between users and groups, into a “payload” table has a workaround.

Thanx sbelini,

I will look into this.

I have been reading this documentation regarding adding and removing in the collection:

http://drc.ideablade.com/xwiki/bin/view/Documentation/CreatingEntities#HAddingandRemovingRelatedObjectsusingAdd2829andRemove2829

As I say, it works to add to the collection, but I get an exception when removing and saving. Why do I get this exception?

Entity Save Error: System.Data.OptimisticConcurrencyException: Store update, insert, or delete statement affected an unexpected number of rows (0). Entities may have been modified or deleted since entities were loaded. Refresh ObjectStateManager entries. at System.Data.Mapping.Update.Internal.UpdateTranslator.ValidateRowsAffected(Int64 rowsAffected, UpdateCommand source) at System.Data.Mapping.Update.Internal.UpdateTranslator.Update(IEntityStateManager stateManager, IEntityAdapter adapter) at System.Data.EntityClient.EntityAdapter.Update(IEntityStateManager entityCache) at System.Data.Objects.ObjectContext.SaveChanges(SaveOptions options) at IdeaBlade.EntityModel.Edm.EdmSaveExecutor.ProcessSaves(IEnumerable`1 groupsByType) at IdeaBlade.EntityModel.Edm.EdmSaveExecutor.SaveWithinContext() at IdeaBlade.EntityModel.Edm.EdmSaveExecutor.Save(DataSourceResolver dataSourceResolver, IDataSourceKey dsKey, SaveWorkState workState)

Hi danjal,

We have a database table called EntUser.

The table contains, among others, the fields: p_userID and p_isGroup.

The table contains our users and groups, and p_isGroup determines whether the entity is a user or group.

What users that are in what groups is determined in an second table called EntUserGroups.

This table has two fields: p_userID and p_groupID

Ideablade Entity model gives us the opportunity to see what groups a user is in by this statement:

p_currentUser.p_userGroups;

And what users that are in a group:

p_currentGroup.p_users;

On my UI, I have two ListBoxes: one shows all groups and the second shows the groups that a current user is in. Between these ListBoxes are two buttons: Add and Remove.

When I add or remove a group to/from the current users groups, a Save button shall become enabled – this works fine by looking at the entitymanager.EntityChanged event.

The code behind the Add button looks something like this:

protected void OnAddGroup(EntUser newValue)

        {

            p_currentUser.p_userGroups.Add(newValue);

            p_currentUser.EntityAspect.SetModified();

        }

This works fine, but I have to use SetModified to trigger the entitymanager.EntityChanged event.

My question here: is this the right way to do this?

The code behind the Remove button looks something like this:

protected void OnRemoveGroup(EntUser newValue)

        {

            p_currentUser.p_userGroups.Remove(newValue);

            p_currentUser.EntityAspect.SetModified();

        }

This does not remove the group from p_userGroups. I get this exception when I save: