Question

I’m literally going crazy with this. I receive from the HTML the data of one “Father” entity, along with the data of three child entities.

In my modelbinder, I create stub entities for relationships, containing only the primary key.

This is my ModelBinder code:

public object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
    {
        DefaultModelBinder binder = new DefaultModelBinder();
        var estimate = (Estimate)binder.BindModel(controllerContext, bindingContext);

        estimate.Id = Guid.NewGuid();
        estimate.OwnerSociety = ModelBinderHelper.MapComplexType<OwnerSociety, int>(controllerContext, "OwnerSociety", int.Parse, c => c.IDOwnerSociety);
        estimate.EstimateType = ModelBinderHelper.MapComplexType<EstimateType, Guid>(controllerContext, "EstimateType", Guid.Parse, c => c.Id);
        estimate.Brand = ModelBinderHelper.MapComplexType<Brand, int>(controllerContext, "Brand", int.Parse, c => c.IDBrand);
        estimate.FromAccount = ModelBinderHelper.MapComplexType<User, int>(controllerContext, "FromAccount", int.Parse, c => c.IDUser);
        estimate.ManagerDirector = ModelBinderHelper.MapComplexType<User, int>(controllerContext, "ManagerDirector", int.Parse, c => c.IDUser);

        estimate.Projects.Add(new Project
        {
            StrategicPlanner = ModelBinderHelper.MapComplexType<User, int>(controllerContext, "StrategicPlanner_1", int.Parse, c => c.IDUser),
            Activity = ModelBinderHelper.MapComplexType<Activity, int>(controllerContext, "Activity_1", int.Parse, c => c.IDActivity),
            ProjectState = ModelBinderHelper.MapComplexType<ProjectState, int>(controllerContext, "ProjectState_1", int.Parse, c => c.IDProjectState),
            StartDate = DateTime.Now,
            Name = "XXX1",
            Brand = estimate.Brand,
            ProjectTypes = new ProjectTypes { IDProjectType = 1 },
            Consuntivo = 0,
            Order = 1
        });
        estimate.Projects.Add(new Project
        {
            StrategicPlanner = ModelBinderHelper.MapComplexType<User, int>(controllerContext, "StrategicPlanner_2", int.Parse, c => c.IDUser),
            Activity = ModelBinderHelper.MapComplexType<Activity, int>(controllerContext, "Activity_2", int.Parse, c => c.IDActivity),
            ProjectState = ModelBinderHelper.MapComplexType<ProjectState, int>(controllerContext, "ProjectState_2", int.Parse, c => c.IDProjectState),
            StartDate = DateTime.Now,
            Name = "XXX2",
            Brand = estimate.Brand,
            ProjectTypes = new ProjectTypes { IDProjectType = 1 },
            Consuntivo = 0,
            Order = 2
        });
        estimate.Projects.Add(new Project
        {
            StrategicPlanner = ModelBinderHelper.MapComplexType<User, int>(controllerContext, "StrategicPlanner_3", int.Parse, c => c.IDUser),
            Activity = ModelBinderHelper.MapComplexType<Activity, int>(controllerContext, "Activity_3", int.Parse, c => c.IDActivity),
            ProjectState = ModelBinderHelper.MapComplexType<ProjectState, int>(controllerContext, "ProjectState_3", int.Parse, c => c.IDProjectState),
            StartDate = DateTime.Now,
            Name = "XXX3",
            Brand = estimate.Brand,
            ProjectTypes = new ProjectTypes { IDProjectType = 1 },
            Consuntivo = 0,
            Order = 3
        });

        return estimate;
    }

When I try to simply attach my father entity, declare it and the child properties as Added, I get the “there is already an object in the objectstatemanager with the same key”. If I try to insert the father entity without childs, it works.

I tried another “way”. The following code:

public Estimate CreateEstimate(Estimate toCreate)
    {
        var brand = Brands.First(c => c.IDBrand == toCreate.Brand.IDBrand);
        var estimateType = EstimateTypes.First(c => c.Id == toCreate.EstimateType.Id);
        var account = Users.First(c => c.IDUser == toCreate.FromAccount.IDUser);
        var manager = Users.First(c => c.IDUser == toCreate.ManagerDirector.IDUser);
        var owner = OwnerSocieties.First(c => c.IDOwnerSociety == toCreate.OwnerSociety.IDOwnerSociety);

        toCreate.Brand = brand;
        toCreate.EstimateType = estimateType;
        toCreate.FromAccount = account;
        toCreate.ManagerDirector = manager;
        toCreate.OwnerSociety = owner;

        foreach (var project in toCreate.Projects)
        {
            project.Activity = Activities.First(c => c.IDActivity == project.Activity.IDActivity);
            project.ProjectState = ProjectStates.First(c => c.IDProjectState == project.ProjectState.IDProjectState);
            project.StrategicPlanner = Users.First(c => c.IDUser == project.StrategicPlanner.IDUser);
            project.ProjectTypes = _entities.ProjectTypes.First();
        }

        _entities.EstimateSet.AddObject(toCreate);

        return toCreate;
    }

But it doesn’t work, telling me that “INSERT on table “Activities” fails because column “Name” can’t be null”. But it really shouldn’t be inserting anything in the Activity table, in fact I’m retrieving the Activity items from the DB and using them.

Funny, the following code works:

public Estimate CreateEstimate(Estimate toCreate)
    {
        var estimate = new Estimate();

        var brand = Brands.First(c => c.IDBrand == toCreate.Brand.IDBrand);
        var estimateType = EstimateTypes.First(c => c.Id == toCreate.EstimateType.Id);
        var account = Users.First(c => c.IDUser == toCreate.FromAccount.IDUser);
        var manager = Users.First(c => c.IDUser == toCreate.ManagerDirector.IDUser);
        var owner = OwnerSocieties.First(c => c.IDOwnerSociety == toCreate.OwnerSociety.IDOwnerSociety);

        estimate.Id = toCreate.Id;
        estimate.Brand = brand;
        estimate.EstimateType = estimateType;
        estimate.FromAccount = account;
        estimate.ManagerDirector = manager;
        estimate.OwnerSociety = owner;
        estimate.Date = toCreate.Date;
        estimate.Subject = toCreate.Subject;
        estimate.Status = toCreate.Status;
        estimate.Language = toCreate.Language;

        foreach (var project in toCreate.Projects)
        {
            var project1 = new Project();
            project1.Activity = Activities.First(c => c.IDActivity == project.Activity.IDActivity);
            project1.ProjectState = ProjectStates.First(c => c.IDProjectState == project.ProjectState.IDProjectState);
            project1.StrategicPlanner = Users.First(c => c.IDUser == project.StrategicPlanner.IDUser);
            project1.StartDate = project.StartDate;
            project1.Name = project.Name;
            project1.Brand = brand;
            project1.ProjectTypes = _entities.ProjectTypes.First();
            estimate.Projects.Add(project1);
        }

        _entities.EstimateSet.AddObject(estimate);

        return toCreate;
    }

But this means recreating the father entity, copying over the values, then recreating every child entity, copying the values, assigning it to the father entity, etc. That’s a pain, and I don’t want to write verbose code like this.

ORM should ease me of the pain of writing tons of code for CRUD operations but it seems like this is not the case.

Anyone can help me?

Answer 1

I had the exact same problem, and had the exact same pains when trying to use EF in a disconnected scenario. And I solved it the same way as you did: reload the object, and ‘replay’ the changes on the domain object (you have to apply a trick to make optimistic concurrency work though). This was the only way I found to make it work.

Another way to make this work is to send the original entity together with the modified entity. Then you don’t have to reload it, but just attach the original entity and replay the changes. But I’m not sure about the overhead if you send all data twice, don’t really like that.

Any other way, just fails, crashes, because it seems to mix up contexts, even if they are disposed already.