c# - 无法使用集合初始值设定项初始化类型 "x"，因为它未实现 'System.Collections.IEnumerable'

Question

我正在尝试使用 linq to sql 和 ViewModel 连接 3 个表，将查询传递给 View 并显示结果，但它不起作用。

更新
DbContext 类:

public partial class DbEntities : DbContext
{
    public DbSet<Foo> Foos{ get; set; }
    public DbSet<Bar> Bars{ get; set; }
    public DbSet<Fubar> Fubars{ get; set; }
}

View 模型:

public class MyViewModel
{
    public Foo Foo{ get; set; }
    public Bar Bar{ get; set; }
    public Fubar Fubar{ get; set; }
}

Controller :

public ActionResult Index(string searchString)
    {
      //var db = new MyViewModel();  //wrong
        var db = new DbEntities();

        var query = (from f in db.Foos
                     join b in db.Bars on f.IDFoo equals b.IDFoo
                     join fb in db.Fubars on b.IDBar equals fb.IDBar
                     select new MyViewModel { 
                                f.IDFoo,
                                f.NameFoo, 
                                f.CityFoo, 
                                b.NameBar, 
                                fb.NameFubar });


        if (!String.IsNullOrEmpty(searchString))
        {
            query = query.Where(x => x.NameFubar.Contains(searchString));
        }
        return View(query);
    }

查看:

@model IEnumerable<Proj.Models.MyViewModel>

@using (Html.BeginForm())
    {
        <p>
            @Html.TextBox("SearchString")
            <input type="submit" class="no-button" value="Search" />
        </p>
    }

@foreach (var item in Model)
{
   <div class="title">@Html.DisplayFor(modelItem => item.NameFubar)</div><br />
   ...

}

我收到以下错误:

1. "Cannot initialize type 'Proj.Models.MyViewModel' with a collection initializer because it does not implement 'System.Collections.IEnumerable' "

Answer 1

问题是我必须在 MyViewModel 中设置属性而不是类:

public short IDFoo { get; set; }
public string NameFoo { get; set; }
public string CityFoo { get; set; }
public string NameBar { get; set; }
public string NameFubar { get; set; }

在 linq 查询中我使用的是集合初始化器而不是对象初始化器:

select new MyViewModel {
       IDFoo = f.IDFoo,
       NameFoo = f.NameFoo,
       CityFoo = f.CityFoo,
       NameBar = b.NameBar,
       NameFubar = fb.NameFubar 
       };