使用下拉列表和Viewmodel在视图中过滤网格

Question

我想用viewmodel中的dropdownlist过滤网格中的数据，但是我不知道该怎么做。 我想创建这样的控制器： 我的控制器：

public ActionResult Index()
    {
        var missions = this.db.missions_supportmission
            .Include(m => m.organization_desk)
            .Include(m => m.organization_programme)
            .Select(x => new MissionsViewModel()
            {                   
                DeskIdSelected = x.organization_desk.name_en,
                ProgrammeIdSelected = x.organization_programme.name_en,
                DeskList = new SelectList(this.db.organization_desk.ToDictionary(b => b.desk_id, b => b.name_en), "Key", "Value"),
                ProgrammeList = new SelectList(this.db.organization_programme.ToDictionary(b => b.prog_id, b => b.name_en), "Key", "Value")
    });

在视图模型中，我有这个：

public class MissionsViewModel
{
    public missions_supportmission missions_supportmission { get; set; }

    [Required]
    public string DeskIdSelected { get; set; }

    [Required]
    public string ProgrammeIdSelected { get; set; }

    [Required]
    public string CountryIdSelected { get; set; }

    [Required]
    public string NatureIdSelected { get; set; }

    [Required]
    public string DirectionIdSelected { get; set; }

    [Required]
    public string UnitIdSelected { get; set; }

    [Required]
    public string TypeIdSelected { get; set; }

    public SelectList DeskList { get; set; }

    public SelectList ProgrammeList { get; set; }
    public SelectList TypeList { get; set; }
    public SelectList CountryList { get; set; }
    public SelectList NatureList { get; set; }
    public SelectList DirectionList { get; set; }
    public SelectList UnitList { get; set; }
}

我的视图（在下拉列表中，我使用了第一个viewbag，但是我不再想要使用它。我想使用强类型代码）

@model IEnumerable<MissionsDF.Models.MissionsViewModel>

        
            
                
Filtres
            

            @using (Html.BeginForm("Index", "Missions", FormMethod.Get))
            {
                
                    
Localisation
                    
                        @Html.LabelFor(model => model, "Desk", htmlAttributes: new { @class = "control-label col-md-4" })
                        
                            @Html.DropDownList("SelectedDesk",
                            new SelectList(ViewBag.Listedesdesks, "Value", "Text", "ViewBag.SelectedDesk"),
                            "All", new { onchange = "form.submit();", @class = "form-control" })
                        
                    
                
            }
        

    
        
Missions
        

            @Html.ActionLink("Create New", "Create")
        
        
            @using (Html.BeginForm("Index"))
            {
                
                    
                        @Html.ActionLink("Pays", "Index",
                        new { SortOrder =ViewBag.ListorderPays,
                            /*SelectedDesk = ViewBag.ListorderPays,
                            SelectedProgramme = ViewBag.ListorderDate,*/
                        })
                    
                    
                        @Html.ActionLink("Date", "Index",
                        new { SortOrder = ViewBag.ListorderDate,
                            /*SelectedDesk = ViewBag.ListorderPays,
                            SelectedProgramme = ViewBag.ListorderDate,*/
                        })
                    
                    
                        Personne
                    
                    
                        Missions
                    
                    
                    
                
            }
            @foreach (var item in Model)
            {
                
                    
                        @Html.DisplayFor(modelItem => item.DeskIdSelected)
                    
                    
                        @Html.DisplayFor(modelItem => item.ProgrammeIdSelected)
                    
                
            }
        
    

 

调试项目时出现以下错误

System.NotSupportedException: 'Only parameterless constructors and initializers are supported in LINQ to Entities.'

我知道错误的出处，但我不知道如何在控制器中编写我的代码，以便一次在网格中显示一个网格和一个下拉列表以使用viewmodel过滤数据。

感谢您的帮助！