MVC3 DropDownListFor没有检索项目的命名（ViewBag用于检索） [英] MVC3 DropDownListFor is not retrieving naming of the items (ViewBag Is used for retrieval)

问题描述

亲爱的编程社区，



尝试从数据库/模型中检索称呼列表并将它们放入我的DropDownListFor控件时，我遇到以下问题。 br />


我目前正在使用一个视图包来获取项目列表，但是没有具有正确名称的项目，我得到没有值的项目。由viewbag从数据库中检索的每个项目在我的下拉列表中简单地表示为System.Web.Mvc.SelectListItem。请看下面的代码：





控制器：

  //    
  //  获取：/患者/创建 
 [授权] 
  public  ActionResult Create（）
 {
 ViewBag.Patient_ward_id =  new  SelectList（db.Wards，   Ward_id，  Ward_name< /跨度>）; 
 ViewBag.Patient_salutation_id =  new  SelectList（db.Salutations，  Salutation_id）; 
 
  return 查看（）; 
} 
 
  //    
  //   POST：/ Patient / Create  
 
 [HttpPost] 
 [授权] 
  public  ActionResult Create（PatientModel patientmodel）
 {
  if  （ModelState.IsValid）
 {
 db.Patients.Add（patientmodel）; 
 db.SaveChanges（）; 
  return  RedirectToAction（  Index）; 
} 
 
  return 查看（patientmodel）; 
} 

查看：

< div  class  =    editor-label >  
 @ Html.LabelFor（model = < span class =code-keyword>>  model.Salutation_id，  Salutation ）
 < /   div  >  
< div  class  =   editor-field >  
 @ * @ Html.DropDownList（  Patient_salutation_id）* @ 
 @ * @ Html.DropDownListFor（model = > 型号.Salutat ion_id， new  SelectList（Model.Salutation，  Salutation_id ，  Salutation_name））* @ 
 @ Html.DropDownListFor（model = >  model.Salutation_id， new  SelectList（ViewBag.Patient_salutation_id，  Salutation_id））
 @ Html.ValidationMessageFor（model = >  model.Salutation_id）
 < /   div  >  
 
< div  class  =   editor-label >  
 @ Html.LabelFor（model = >  model.PatientDateOfBirth）
 < /   div  >  
< div  class  =    editor-field >  
 @ Html.EditorFor（model = >  model.PatientDateOfBirth）
 @ Html.ValidationMessageFor（model = >  model.PatientDateOfBirth ）
 < /   div  >  

欢迎任何意见或建议。

解决方案

试试这样

为DropDownList添加一个公共类，如下所示

  public   static   class  DropDownList< t> 
 {
  public   static  SelectList LoadItems（IList< t> collection， string   value ， string  text）
 {
  return   new  SelectList（collection， value ，text）; 
} 
} 
从控制器调用方法，如下所示。 
 ViewData [ 管理员] = 
 DropDownList< executive> .LoadItems（ 
 objExecutivesDbContext.Executives.ToList（），  ExecutiveId，  ExecutiveName）; 
从视图中调用viewData  
< div  class  = < span class =code-string>  editor-field >  
 @ Html.DropDownListFor（model = >  model.ExecutiveId，（IEnumerable< selectlistitem>）ViewData [ 执行]，   - 选择 - ）

Dear programming community,

I have the following problem when trying to retrieve a list of salutations from the database/model and putting them in my DropDownListFor control.

I am currently using a viewbag to get the list of items but instead of items with proper names i get items with no values. Each item retrieved from the database by a viewbag is simply represented as "System.Web.Mvc.SelectListItem" in my dropdown list. Please see the code below:


Controller:

//
        // GET: /Patient/Create
        [Authorize]
        public ActionResult Create()
        {
            ViewBag.Patient_ward_id = new SelectList(db.Wards, "Ward_id", "Ward_name");
            ViewBag.Patient_salutation_id = new SelectList(db.Salutations, "Salutation_id");

            return View();
        } 

        //
        // POST: /Patient/Create

        [HttpPost]
        [Authorize]
        public ActionResult Create(PatientModel patientmodel)
        {
            if (ModelState.IsValid)
            {
                db.Patients.Add(patientmodel);
                db.SaveChanges();
                return RedirectToAction("Index");  
            }

            return View(patientmodel);
        }

View:

<div class="editor-label">
            @Html.LabelFor(model => model.Salutation_id, "Salutation")
        </div>
        <div class="editor-field">
       @* @Html.DropDownList("Patient_salutation_id")*@
           @* @Html.DropDownListFor(model => model.Salutation_id, new SelectList(Model.Salutation, "Salutation_id", "Salutation_name"))*@
           @Html.DropDownListFor(model => model.Salutation_id, new SelectList(ViewBag.Patient_salutation_id, "Salutation_id"))
            @Html.ValidationMessageFor(model => model.Salutation_id)
        </div>

        <div class="editor-label">
            @Html.LabelFor(model => model.PatientDateOfBirth)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.PatientDateOfBirth)
            @Html.ValidationMessageFor(model => model.PatientDateOfBirth)
        </div>

Any comments or suggestions are welcome.

解决方案

Try like this
Add a common class for DropDownList like below

public static class DropDownList<t>
   {
       public static SelectList LoadItems(IList<t> collection, string value, string text)
       {
           return new SelectList(collection, value, text);
       }
   }
Call the method from the controller like Below.
ViewData["Executives"] =
                DropDownList<executives>.LoadItems(
                    objExecutivesDbContext.Executives.ToList(), "ExecutiveId", "ExecutiveName ");
Call the viewData from the View like below
<div class="editor-field">
            @Html.DropDownListFor(model => model.ExecutiveId, (IEnumerable<selectlistitem>) ViewData["Executives"], "--Select--")

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