HTML.DropDownListFor 不将参数传递给控制器​​？

Question

我现在正在尝试过滤我的视图几个小时。这就是我所拥有的： 我的观点：

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

在我的模型类中：

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

我的控制器：

//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
            }

当我尝试选择一个并单击回车时，它应该正在传递，因为在我的浏览器中我检查了它并且它正在传递查询参数：

但在我的控制器中，我的 departamentoSelecionado 为空，下拉列表也再次获得“选择”，而不是保留我之前选择的内容！任何帮助表示赞赏！

Answer 1

将 departamentoSelecionado 更改为 departmentoSelecionado 。您在 departmentoSelecionado 中拼写了一个额外的字母 a。

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

action方法中的参数要和f => f.DepartmentoSelecionado一样。

2020 年 9 月 16 日更新

控制器代码

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);
    }
}

视图代码

@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" />
}

型号代码

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

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

测试