HTML.DropDownListFor不将参数传递给控制器​​？

如何解决HTML.DropDownListFor不将参数传递给控制器​​？

我现在要过滤几个小时的视图。这就是我所拥有的： 我的看法：

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

在我的模型课中：

 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Enter时，它被认为是通过的，因为在我的浏览器中我检查了它并且正在传递查询参数：

https://snipboard.io/HvnmqO.jpg

但是在我的控制器中，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！

解决方法

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方法中的参数应该与f => f.DepartmentoSelecionado相同。

更新16/09/2020

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);
    }
}

查看代码

@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