Question

我试图在我的一个CRUD屏幕中创建一个基于程序中不同模型的下拉列表。现在，它根据ID输入值，但我希望它能够在下拉列表中填充讲师的姓名。

我已经使用选择列表尝试了一些其他操作，但似乎没有用。

这是我的模特

     [Table("Section")]
    public class Section
    {
        [Key]
        public int Id { get; set; }


        [DisplayName("Section")]
        public int? section { get; set; }

        public Nullable <int> instructor_id { get; set; }
        public int location_id { get; set; }
        public int modality_id { get; set; }
        public int DOW_id { get; set; }
        public int course_id { get; set; }

        public virtual DOW DOW { get; set; }
        public virtual Instructor Instructor { get; set; }
        public virtual Location Location { get; set; }
        public virtual Modality Modality { get; set; }
        public virtual Course Course { get; set; }

这是我的控制者：

 // GET: Sections/Create
        public ActionResult Create()
        {
            return View();
        }

        // POST: Sections/Create
        // To protect from overposting attacks, please enable the specific properties you want to bind to, for 
        // more details see https://go.microsoft.com/fwlink/?LinkId=317598.
        [HttpPost]
        [ValidateAntiForgeryToken]
        public ActionResult Create([Bind(Include = "Id,section,startTime,endTime,startDate,endDate,isTap,isActive,instructor_id,location_id,modality_id,DOW_id,course_id")] Section section)
        {
            if (ModelState.IsValid)
            {
                db.Sections.Add(section);
                db.SaveChanges();
                return RedirectToAction("Index");
            }
            //ViewBag.instruct = new SelectList(db.Instructors, "Id", "lname", section.instructor_id);

            return View(section);
        }

这是我的观点

  <div class="form-group">
            @Html.LabelFor(model => model.instructor_id, "instructor_id" , htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                @Html.EditorFor(model => model.instructor_id, new { htmlAttributes = new { @class = "form-control" } })
                @Html.ValidationMessageFor(model => model.instructor_id, "", new { @class = "text-danger" })
            </div>
        </div>

Answer 1

以表格John Peters的答案，请看

创建一个数据层，以检索所需列表。然后使用EF获取所有状态。

//assuming you have a table of states..
var states = db.States();

状态表应该是唯一的状态列表。

var selectList = new List<SelectListItem>(); 
foreach(var thing in states){
    //if you got everything, thus the ID field for the value...   
   selectList.Add(new SelectListItem {Text =thing.State, Selected = false, Value = thing.ID);
}

确保在Viewmodel类中，选择列表是公共属性.....并设置为您在上方所做的操作。您还需要为返回的视图选择提供一个字符串。

StatesSelectList = selectList;
public IEnumberable<SelectListItem> StatesSelectList {get;set;}
public string SelectedState {get;set;}

在您看来，请执行以下操作：

@Html.DropDownListFor(p=>Model.SelectedState, Model.StatesSelectList)

Answer 2

您需要按以下方式更改Controller中的Get方法：

// GET: Sections/Create
    public ActionResult Create()
    {
        ViewBag.Instructors = db.Instructors.ToList();

        return View();
    }

您的HTML需要进行如下更改：

 <div class="form-group">
            @Html.LabelFor(model => model.instructor_id, "instructor_id" , htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                @Html.DropDownListFor(model => model.instructor_id, new SelectList(ViewBag.Instructors, "Id", "Name"), new { @class = "form-control" } )
                @Html.ValidationMessageFor(model => model.instructor_id, "", new { @class = "text-danger" })
            </div>
        </div>

确保字段名称正确。

如何基于SQL数据库中的ID填充下拉列表

2 个答案: