HTML.DropDownListFor not passing parameter to controller?

Question

i am trying to filter my view for a couple of hours by now. This is what i have: My View:

@using (Html.BeginForm("Index", "RH_CentroCusto", FormMethod.Get))
{
   @Html.DropDownListFor(f => f.DepartmentoSelecionado , Model.Departamentos, "Select")
}

in my Model Class :

 public IEnumerable<SelectListItem> Departamentos { get; set; }
 public string DepartmentoSelecionado { get; set; }

My controller:

//i want to receive the value in departamentoSelecionado !!
 public IActionResult Index( string searchString, string departamentoSelecionado = "", int page = 1)
     
     
            List<SelectListItem> selectList = new List<SelectListItem>();

            foreach (var x in _context.RH_Departamento.ToList())
            {
                selectList.Add(new SelectListItem() { Text = x.Departamento , Value = x.Departamento           });
            }

//and then i add to the viewModel that i create the list
        ViewModelCentroCusto vmcc = new ViewModelCentroCusto()
            {  
                   Departamentos = selectList
            }

When i try to select one and click enter, it is suposed to be passing because in my browser i inspected and it was passing query parameters:

But in my controller my departamentoSelecionado is null, also the dropdown list gets the "select" again instead of keeping what i choose before! Any help is appreciated!

Answer 1

Change departamentoSelecionado to departmentoSelecionado . You spelt an extra letter a in departmentoSelecionado .

//public IActionResult Index( string searchString, string departamentoSelecionado = "", int page = 1)
  public IActionResult Index( string searchString, string departmentoSelecionado = "", int page = 1)

The parameter in action method should be same as f => f.DepartmentoSelecionado.

Update 16/09/2020

Codes of controller

public class RH_CentroCustoController : Controller
{
   
    //i want to receive the value in departamentoSelecionado !!
    public IActionResult Index(string searchString, string departmentoSelecionado ="", int page = 1)
    {
        List<SelectListItem> selectList = new List<SelectListItem>();

        IList<RH_Departamento> RH_Departamento = new List<RH_Departamento>(){
            new RH_Departamento(){ Departamento="dep1" },
            new RH_Departamento(){ Departamento="dep2" },
            new RH_Departamento(){ Departamento="dep3" },
        };//just for test 
        //foreach (var x in _context.RH_Departamento.ToList())
        foreach (var x in RH_Departamento.ToList())
        {
            selectList.Add(new SelectListItem() { Text = x.Departamento, Value = x.Departamento });
        }

        //and then i add to the viewModel that i create the list
        ViewModelCentroCusto vmcc = new ViewModelCentroCusto()
        {
            Departamentos = selectList
        };

        return View(vmcc);
    }
}

Codes of View

@model xxx.Models.ViewModelCentroCusto
@{
    Layout = null;
}

@using (Html.BeginForm("Index", "RH_CentroCusto", FormMethod.Get))
{
    @Html.DropDownListFor(f => f.DepartmentoSelecionado, new SelectList(Model.Departamentos, "Value", "Text"), "Select");
    <input type="submit" value="Save" />
}

Codes of Model

public class ViewModelCentroCusto
{
    public IEnumerable<SelectListItem> Departamentos { get; set; }
    public string DepartmentoSelecionado { get; set; }
}

public class RH_Departamento
{
    public string Departamento { get; set; }
}

Test