Send only object from the list that has changed to the controller

Question

I own a view who lists all my customers. Each customer has 3 checkbox where the user selects them, and sends them to the controller - through the button (Submit) - the data to change. The method is working perfectly. However, when sending, it sends all customers, even those that have not changed. Thus it updates all (even those that have not been modified). This does not cause me problems, but causes a delay (since he has to go through the entire list to change).

I would like to know if there is a way to check if the client has been modified, and send only those who have been to my controller.

My View is that way:

@using PrestacaoWeb.UI.Helpers
@model List<PrestacaoWeb.Application.ViewModels.ClientePrestacaoViewModel>

@using (Html.BeginForm("EditarMes", "Cliente", FormMethod.Post))
{
    <input type="submit" value="Salvar"/>

<table>
    <thead>
        <tr>
        <th> Cliente </th>
        <th> 1 </th>
        <th> 2 </th>
        <th> 3 </th>
        <th> Cidade </th>
        <th> Responsável </th>
        <th> Obs </th>
        </tr>
    </thead>
        <tbody>
        @for (int i = 0; i < Model.Count(); i++)
        {
            <tr>
                @Html.HiddenFor(model => model[i].ClienteId)
                <td style="width: 100px">
                    <p align="center">@Model[i].NomeCliente</p>
                </td>
                <td style="width: 20px"><p align="center"> <b>@Html.CheckBoxFor(model => Model[i].EnvioPrestacao.bJaneiro)</b> </p> </td>

                <td style="width: 20px"><p align="center"> <b>@Html.CheckBoxFor(model => Model[i].EnvioPrestacao.bFevereiro)</b> </p> </td>

                <td style="width: 20px"><p align="center"> <b>@Html.CheckBoxFor(model => Model[i].EnvioPrestacao.bMarco)</b> </p> </td>
                 <td>
                    @Model[i].Cliente.Cidade.Nome
                </td>

                <td style="width: 100px">
                    <p align="center">@Model[i].Responsavel</p>
                </td>
                    <td style="width: 210px">
                        <p align="center">@Model[i].Observacao.</p>
                    </td>

            </tr>

        }
        </tbody>
</table>
}

By clicking the button Save, it sends all objects from the list to the method Editarmes, in my Controller.

[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult EditarMes(IList<ClientePrestacaoViewModel> prestacaoViewModel)
{
    if (!ModelState.IsValid) return View("Index");
    foreach (var item in prestacaoViewModel.Where(item => item != null))
    {
        _clienteContext.Atualizar(item);
        TempData["MensagemSuccess"] = "Cliente alterado com sucesso!";

    }
    return Redirect(ControllerContext.HttpContext.Request.UrlReferrer.ToString());
}

If I change all clients, you’re right, it will take a while. Now, if I change only one customer, and it sends 30 to controller, it wouldn’t be "nice" to wait for this.

Answer 1

It is cheaper in processing cost to bring the original list and compare the values.

Apparently you use a repository, so I don’t know how it’s done, but using an Entity Framework context would be something like this:

var listaOriginal = contexto.ClientePrestacoes.AsNoTracking().Where(/* Condição */).ToList();

foreach (var item in prestacaoViewModel.Where(item => item != null))
{
    var itemOriginal = listaOriginal.Single(l => l.Id == item.Id);
    if (item.bJaneiro != itemOriginal.bJaneiro || item.bFevereiro != itemOriginal.bFevereiro || item.bMarco != itemOriginal.bMarco) {
        _clienteContext.Atualizar(item);
    }

    TempData["MensagemSuccess"] = "Cliente alterado com sucesso!";
}

Taking advantage, this is not good practice:

if (!ModelState.IsValid) return View("Index");

In this command, you stop implementing the default behavior of MVC, which is to return the same screen in case of invalidity of some information on screen, and do not load any data that serves to fill the screen.