C# MVC EF5 delete relationships

Question

Hello, I am developing an application using C# MVC and EF5 and I have the following problem: I have a customer group management screen, in this group I can insert and remove customers, I use a relationship table between clients and groups called client_group_client (obviously it has relationship with the client_group table), when I add a customer to this group, I insert their information into a table on the screen:

The code of each of these lines goes something like this:

<button class="btn_remove">Remover</button> <input name="client_group_client[0].id_client" type="hidden" value="3">

<input name="client_group_client[0].id" type="hidden" value="3">

<input name="client_group_client[0].status" type="hidden" value="1">

<input name="client_group_client[0].datetime_inclusion" type="hidden" value="15/07/2014 10:06:24">

Cliente 3

if I insert a new account and save, will insert a record in the bank, until then it is working, the problem is when I try to remove one of these records, the object passed to the comes only with active relations on the screen, I don’t know which one was removed so I could remove it from the bank. Does anyone have any idea how to do this?

controller Clientgroupcontroller:

[HttpPost]
    [ValidateAntiForgeryToken]
    public ActionResult Edit(client_group client_group, string actionSubmit, string urlReferrer)
    {
        repository.BeforeUpdate(client_group);
        if (!repository.Save())
        {
            setFlash("danger", repository.GetHtmlErrors());
            return View("~/Views/Person/ClientGroup/Edit.cshtml", client_group);
        }

        setFlash("success", I18n.T("Alert","RegisterSaveSucess"));


        if (actionSubmit == "saveAndBack")
            return Redirect(urlReferrer);
        else
            return View("~/Views/Person/ClientGroup/Edit.cshtml", client_group);
    }

Repository class (created by me to process data before/after modifying):

public override bool BeforeUpdate(client_group obj)
    {
        foreach (client_group_client register in obj.client_group_client)
        {
            register.id_client_group = obj.id;

            if (register.datetime_inclusion == null)
            {
                register.datetime_inclusion = DateTime.Now;
                register.status = client_group_client.ACTIVE;
                dbContext.Entry(register).State = EntityState.Added;
            }
            else
            {
                dbContext.Entry(register).State = EntityState.Modified;
            }
        }

        return base.BeforeUpdate(obj);
    }

Answer 1

One of the ways to solve it is:

• Get the group’s customer list as it is in your database (just so you know which one has been removed);

• Change/Update the customer list as you remove/edit the group’s clients and save

Example:

[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Edit(client_group client_group, string actionSubmit, string urlReferrer)
{        
    //Obter a lista de clientes do grupo como está na sua base de dados
    var grupo = repository.ObterGrupoPorId(client_group.IdGroup);
    //Diferença entre as listas para você alterar/atualizar a lista de clientes
    var clientesPosEdicao = ObterClientesInformadosUsuario(client_group).Except(grupo.Clientes).ToList();
    //Alterar/Atualizar a lista de clientes do grupo
    grupo.Clientes = clientesPosEdicao;
    //restante de código desejado para salvar, redirecionar, etc.
}

Note: Code not tested

Answer 2

I believe the fact that you’re sending an instruction to the Controller to which the association record belongs may be the complicator.

The solution I’m going to pass is possibly quite different from what you’ve imagined, but it’s the simplest from the point of view of MVC architecture.

Here’s what I’d do:

1. Change the Remove button to a normal link

@Html.ActionLink("Remover", "Delete", "ClientGroupClient", new { id = client_group_client[0].id })

2. User a Delete Action in the Clientgroupclient Controller, instead of the Clientgroup Controller

// Esta Action pode abrir uma View de confirmação, mas é opcional.
// Você pode implementar apenas a Action mais abaixo.
public ActionResult Delete(int id)
{
    var clientGroupClient = dbContext.ClientGroupClients.Single(x => x.Id == id);
    return View(clientGroupClient);
}

Notice that to call this Action, it needs to be a requisition POST. This is not required, but I usually use this to ensure that there is a confirmation for deletion of the record, just for security.

[HttpPost, ActionName("Delete")]
public ActionResult DeleteConfirmed(int id)
{
    var clientGroupClient = dbContext.ClientGroupClients.Single(x => x.Id == id);
    var clientGroupId = clientGroupClient.ClientGroupId;

    dbContext.ClientGroupClients.Remove(clientGroupClient);
    dbContext.SaveChanges();
    return RedirectToAction("Details", "ClientGroups", new { id = clientGroupId });
}