Question

我的代码就像这样

 namespace DiagnosisApp.Models
{
    public class ProcedurePrice
    {
        public int ID { get; set; }


        public int DepartmentID { get; set; }
        public int ProcedureID { get; set; }
        public int InsuranceProviderID { get; set; }
        public int ProcedureCategoryID { get; set; }
        public int ProcedureSubCategoryID { get; set; }



        [ForeignKey("ID")]
        public virtual Department Department { get; set; }

        [ForeignKey("ID")]
        public virtual InsuranceProvider InsuranceProvider { get; set; }

        [ForeignKey("ID")]
        public virtual ProcedureCategory ProcedureCategory { get; set; }
        [ForeignKey("ID")]
        public virtual ProcedureSubCategory ProcedureSubCategory { get; set; }
    }
}

控制器

  public ActionResult Create()
        {
            ViewBag.DepartmentID = new SelectList(db.Departments, "ID", "Name");
            ViewBag.ProcedureSubCategoryID = new SelectList(db.ProcedureSubCategories, "ID", "Name");
            return View();
        }

在我看来

 @Html.DropDownList("ProcedureID", null, new { @class = "form-control" })
  @Html.ValidationMessageFor(model => model.ProcedureID)

一切看起来都不错，但它会引发错误

There is no ViewData item of type 'IEnumerable<SelectListItem>' that has the key 'ProcedureID'.

有谁可以指出我在这里做错了什么？

Answer 1

错误的是，当您传递ViewBag.ProcedureSubCategoryID int ProcedureID时，您将它放在Html.DropDownList()中，并且您正在传递SelectList参数null。快速解决方法是将ProcedureSubCategoryID替换为ProcedureID Html.DropDownList()作为第一个参数中的关键字：

你有三种解决方法。

方式1：

您可以执行以下操作，而不是在接受类型null的第二个参数中传递SelectList：

@Html.DropDownList("ProcedureID", ViewBag.ProcedureSubCategoryID as SelectList, new  { @class="form-data" })

Way2：

public ActionResult Create()
{
  ViewBag.DepartmentID = new SelectList(db.Departments, "ID", "Name");
  ViewBag.ProcedureSubCategoryID = new SelectList(db.ProcedureSubCategories, "ID", "Name");
  return View();
}


@Html.DropDownList("ProcedureSubCategoryID", null, new { @class = "form-control" })

方式3：

或替代方法是将其存储在您的操作中ProcedureID：

public ActionResult Create()
{
       ViewBag.DepartmentID = new SelectList(db.Departments, "ID", "Name");
       ViewBag.ProcedureID = new SelectList(db.ProcedureSubCategories, "ID", "Name");
       return View();
}

并在视图中：

@Html.DropDownList("ProcedureID", null, new { @class = "form-control" })

Answer 2

我想你错过了像

这样的东西

ViewBag.ProcedureID = new SelectList(db.ProcedureCategory, "ID", "Name");

我认为你必须对ViewBag.ProcedureId进行初始化

Answer 3

你正在使用partial ??

如果你使用partial，那非常简单，你可以找到错误的解决方案此错误表示您没有查看数据类型为SelectListItem，该键为'ProcedureId' 我认为您使用Partial进行创建并在索引页面上调用它因此，您应该将此代码传递给索引操作结果，就像我的代码一样：

public ActionResult Index()
    {
        ViewData["ProcedureID"] = new SelectList(db.Procedures, "ProcedureId", "ProcedureName");
        return View();
    }


    public ActionResult Create()
    {
        return View();
    }

没有类型为'IEnumerable <selectlistitem>'的ViewData项具有键“key”</selectlistitem>

3 个答案:

方式1：

Way2：

方式3：