Dropdownlistfor how to use?

Question

I’m having a question on how popular and then pick up the selected item from a DropDownListFor, I am using DDD architecture and Entity Framework.

In case here my class ServiceProviderViewModel has to have relationship with other classes. I would like to know how to do to popular this Helper in View of Create.

Follows codes:

public class ServiceProviderViewModel
{
    [Key]
    public int ServiceProviderId { get; set; }

    [Required(ErrorMessage = "Por favor, informe o nome do colaborador.")]
    [Display(Name = "Nome:")]
    public string Name { get; set; }

    [Display(Name = "Nome da Mãe:")]
    public string MotherName { get; set; }

    [Display(Name = "Nome do Pai:")]
    public string FatherName { get; set; }

    [Display(Name = "E-mail:")]
    [EmailAddress(ErrorMessage = "Por favor, informe um formato de e-mail válido.")]
    public string Email { get; set; }

    [Display(Name = "Nascimento:")]
    public DateTime Birth { get; set; }

    [ScaffoldColumn(false)]
    public DateTime DateRegister { get; set; }

    [ScaffoldColumn(false)]
    public DateTime DateModified { get; set; }

    [Required(ErrorMessage = "Por favor, informe o departamento para o colocaborador.")]
    [Display(Name = "Departamento:")]       
    public int DepartamentId { get; set; }

    [Required(ErrorMessage = "Por favor, informe o departamento para o colocaborador.")]
    [Display(Name = "Cargo/Função:")]
    public int PositionId { get; set; }

    public virtual DepartamentViewModel Departaments { get; set; }
    public virtual PositionViewModel Positions { get; set; }

    public virtual IEnumerable<ServiceProviderAddressViewModel> ServiceProviderAddress { get; set; }
    public virtual IEnumerable<ServiceProviderPhoneViewModel> ServiceProviderPhone { get; set; }
    public virtual IEnumerable<ServiceProviderInfoViewModel> ServiceProviderInfo { get; set; }
    public virtual IEnumerable<InfoBankViewModel> InfoBank { get; set; }
}

In the Controller:

 public class ServiceProviderController : Controller
{
    private readonly IServiceProviderAppService _serviceProviderApp;

    public ServiceProviderController(IServiceProviderAppService serviceProviderApp)
    {
        _serviceProviderApp = serviceProviderApp;
    }

    // GET: ServiceProvider
    public ActionResult Index()
    {
        var serviceProviderViewModel = Mapper.Map<IEnumerable<ServiceProvider>, IEnumerable<ServiceProviderViewModel>>(_serviceProviderApp.GetAll());
        return View(serviceProviderViewModel);
    }

    // GET: ServiceProvider/Create
    public ActionResult Create()
    {
        return View();
    }

    // POST: ServiceProvider/Create
    [HttpPost]
    public ActionResult Create(ServiceProviderViewModel serviceProvider)
    {
        if (ModelState.IsValid)
        {
            var serviceProviderDomain = Mapper.Map<ServiceProviderViewModel, ServiceProvider>(serviceProvider);
            _serviceProviderApp.Add(serviceProviderDomain);
            _serviceProviderApp.Save();

            return RedirectToAction("Index");
        }

        return View(serviceProvider);
    }

...

For each class that ServiceProvider relates have the models specific to the realization of CRUD. I just don’t know how I should do to run this mixture of models among the views and controllers.

Answer 1

Code taking into account that the Positionid should be a combo:

Na Action Get:

Obs: You must pass the Viewbag.Position

public ActionResult Create()
{
    ViewBag.Position = new SelectList(_serviceProviderApp.SeuMetodoDeObterPositions(), "PositionId", "SeuCampoDescricao");

    return View();
}

In view:

Obs: This Code puts the first option blank and then the data coming from Viewbag.

@Html.DropDownList("PositionId", (IEnumerable<SelectListItem>)ViewBag.Position, String.Empty, new { @class = "form-control" })

Answer 2

@uitan, this Exception is masking the real problem that should only be validation of your form. You must load the Viewbags from the post action as you did in the Get action. your post should look like this:

// POST: ServiceProvider/Create
[HttpPost]
public ActionResult Create(ServiceProviderViewModel serviceProvider)
{
    if (ModelState.IsValid)
    {
        var serviceProviderDomain = Mapper.Map<ServiceProviderViewModel, ServiceProvider>(serviceProvider);
        _serviceProviderApp.Add(serviceProviderDomain);
        _serviceProviderApp.Save();

        return RedirectToAction("Index");
    }

    //FALTAM ESSAS LINHAS:
    ViewBag.Position = new SelectList(_positionApp.GetAll(), "PositionId", "Description");
    ViewBag.Departament = new SelectList(_departamentApp.GetAll(), "DepartamentId", "Description");

    return View(serviceProvider);
}

Mark as solved if it works. :)

Answer 3

In the Domain:

 public class ServiceProvider
{
    #region Attributs
    public int ServiceProviderId { get; set; }
    public string Name { get; set; }
    public string MotherName { get; set; }
    public string FatherName { get; set; }        
    public string Email { get; set; }
    public DateTime Birth{ get; set; }
    public DateTime DateRegister { get; set; }
    public DateTime DateModified { get; set; }
    #endregion
    #region Foreingkeys
    public int DepartamentId { get; set; }
    public int PositionId { get; set; }
    #endregion
    #region Properties Navigations
    public virtual Departament Departaments { get; set; }
    public virtual Position Positions { get; set; }
    #endregion
}

public class Position
{
    #region Attributs
    public int PositionId { get; set; }
    public string Description { get; set; }
    public DateTime DateRegister { get; set; }
    public DateTime DateModified { get; set; }
    #endregion
    #region Relationships Other Class
    public virtual IEnumerable<ServiceProvider> ServiceProviders { get; set; }
    #endregion
}

 public class Departament
{
    #region Attributs
    public int DepartamentId { get; set; }
    public string Description { get; set; }
    public DateTime DateRegister { get; set; }
    public DateTime DateModified { get; set; }
    #endregion
    #region Relationships Other Class
    public virtual IEnumerable<ServiceProvider> ServiceProviders { get; set; }
    #endregion
}

In Viewmodel (Presentation Layer)

public class ServiceProviderController : Controller
{
    private readonly IServiceProviderAppService _serviceProviderApp;
    private readonly IPositionAppService _positionApp;
    private readonly IDepartamentAppService _departamentApp;

    public ServiceProviderController(IServiceProviderAppService serviceProviderApp, IPositionAppService positionApp, IDepartamentAppService departamentApp)
    {
        _serviceProviderApp = serviceProviderApp;
        _positionApp = positionApp;
        _departamentApp = departamentApp;
    }

    // GET: ServiceProvider
    public ActionResult Index()
    {
        var serviceProviderViewModel = Mapper.Map<IEnumerable<ServiceProvider>, IEnumerable<ServiceProviderViewModel>>(_serviceProviderApp.GetAll());
        return View(serviceProviderViewModel);
    }

    // GET: ServiceProvider/Details/5
    public ActionResult Details(int id)
    {
        return View();
    }

    // GET: ServiceProvider/Create
    public ActionResult Create()
    {
        ViewBag.Position = new SelectList(_positionApp.GetAll(), "PositionId", "Description");
        ViewBag.Departament = new SelectList(_departamentApp.GetAll(), "DepartamentId", "Description");
        return View();
    }

    // POST: ServiceProvider/Create
    [HttpPost]
    public ActionResult Create(ServiceProviderViewModel serviceProvider)
    {
        if (ModelState.IsValid)
        {
            var serviceProviderDomain = Mapper.Map<ServiceProviderViewModel, ServiceProvider>(serviceProvider);
            _serviceProviderApp.Add(serviceProviderDomain);
            _serviceProviderApp.Save();

            return RedirectToAction("Index");
        }

        return View(serviceProvider);
    }
}

Na View:

<div class="form-group">
            @Html.LabelFor(model => model.DepartamentId, htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                @Html.DropDownListFor(model => model.DepartamentId, (IEnumerable<SelectListItem>)ViewBag.Departament, string.Empty)
                @Html.ValidationMessageFor(model => model.DepartamentId, "", new { @class = "text-danger" })
            </div>
        </div>

        <div class="form-group">
            @Html.LabelFor(model => model.PositionId, htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                @Html.DropDownListFor(model => model.PositionId, (IEnumerable<SelectListItem>)ViewBag.Position, string.Empty)
                @Html.ValidationMessageFor(model => model.PositionId, "", new { @class = "text-danger" })
            </div>
        </div>

Getall() and CRUD methods are called by generic repositories. The problem is exactly when I try to submit the form. Shows the error I commented earlier.