为什么我不能通过我的ViewData或模型进行操作？

Question

我一直在尝试在视图中迭代我的ViewData时遇到错误...我甚至尝试将视图强行键入IEnumerable（App.Models.Namespace）并使用Model，但无济于事。要么我因为缺少GetEnumerable方法或者无效的类型转换而出错...我知道我是怎么做的吗？

...模型

public IQueryable<Product> getAllProducts()
{
    return (from p in db.Products select p);
}

...控制器

public ActionResult Pricing()
{
    IQueryable<Product> products = orderRepository.getAllProducts();

    ViewData["products"] = products.ToList();

    return View();
}

查看...

<%@ Page Title="" Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage" %>

<asp:Content ID="Content1" ContentPlaceHolderID="TitleContent" runat="server">
    Pricing
</asp:Content>

<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server">

    <h2>Pricing</h2>

    <div>
        <select class="product">
            <%foreach(var prod in ViewData["products"]){%>
                <option><%=prod.Title %></option>
            <%} %>

        </select><select></select>
    </div>

</asp:Content>

Answer 1

使用演员表尝试：

foreach(var prod in (List<Product>)ViewData["products"])

Answer 2

foreach (var prod in (ViewData["products"] as IEnumerable<Product>))

我遇到了类似的情况，这对我有用。

Answer 3

为什么你这样做呢？为什么不这样做：

Inherits="System.Web.Mvc.ViewPage<IEnumerable<Product>>

在你看来

。然后在你的控制器动作中执行：

public ActionResult Pricing()
{
    IQueryable<Product> products = orderRepository.getAllProducts();
    return View(products.ToList(););
}

然后你根本不必使用ViewData。

Answer 4

<%foreach(Product prod in ViewData["products"]){%>

Answer 5

foreach(var prod in ViewData["products"] as IQueryable<Product>)

Answer 6

如果你从两个以上的模型中获取列表，并希望在一个列表中显示两个模型，那么你应该像这样使用.. 首先创建你的两个模型是学生，第二个是教师。

// Create Models
public class Student
{
    public int Id { get; set; }
    public string Name { get; set; }
    public string Address { get; set; }
    public List<int> Marks { get; set; }
}

public class Teacher
{
    public int Id { get; set; }
    public string Name { get; set; }
    public string Address { get; set; }
}

//创建控制器

  public ActionResult Index()
    {
        List<Student> students = new List<Student>()
        {
            new Student {Id = 1, Name = "Vikas", Address = "Mohali", Marks = new List<int> {90, 23, 46,56} },
            new Student {Id = 2, Name = "Rajeev", Address = "Mohali", Marks = new List<int> { 56, 78, 34, 67 }},
            new Student {Id = 3, Name = "Ajay", Address = "Delhi", Marks = new List<int> {56, 78, 34, 56}}
        };

        List<Teacher> teachers = new List<Teacher>()
        {
            new Teacher {Id = 1, Name = "Arun Nagar", Address = "Delhi"},
            new Teacher {Id = 2, Name = "Manish Kumar", Address = "Mohali"}
        };

        var Querylist = (from student in students
                         where student.Address == "Mohali"
                         select student.Name)
                        .Concat(from teacher in teachers
                                where teacher.Address == "Mohali"
                                select teacher.Name);
        //get list in ViewBag
        ViewBag.DataLIst = Querylist;
        //get list in View Data
        ViewData["DataLIst1"] = Querylist.ToList();
        return View(Querylist.AsEnumerable());
    }

//create View "Index.cshtml"   


@foreach (var h in @ViewBag.DataLIst)
{ 
    <h3>@h</h3>
}
@foreach (var s in @ViewData["DataLIst1"] as List< string>)
{
    <h1>@s</h1>
}