ASP.NET MVC View Issue - asp.net

Question

I am trying to resolve the error 'List ActiveOrder02 does not contain a definition for Client' that appears when I put the mouse over '.Client' on the line
#Html.DisplayNameFor(model => model.ActiveOrders02.Client)
in the following View:
#model MVCDemo2.ViewModels.Order02VM
<table class="table">
<tr><th>#Html.DisplayNameFor(model => model.ActiveOrders02.Client)</th></tr>
#foreach (var item in Model.ActiveOrders02)
{
<tr>
<td>#Html.DisplayFor(modelItem => item.Client)</td>
</tr>
}
For info here are the Controller and the ViewModel:
using MVCDemo2.Models;
using MVCDemo2.ViewModels;
using System.Linq;
using System.Web.Mvc;
namespace MVCDemo2.Controllers
{
public class Order02Controller : Controller
{
private InventoryContainer db02 = new InventoryContainer();
// GET: Order02
public ActionResult Index()
{
//Create instance of the (View)Model
var o = new Order02VM();
//Retrieves DATA from the DB
var resultSet02 = db02.SampleDbTable;
// Push the retrieved DATA into the (View)Model
o.ActiveOrders02 = resultSet02.Select(x => new ActiveOrder02
{
ID = x.tableId,
Client = x.tableClient
}).ToList();
//EDIT caused by answer of #David
return View(o);
//IT WAS: return View(o.ActiveOrders02.ToList());
}
}
}
Here follows the ViewModel:
using System.Collections.Generic;
namespace MVCDemo2.ViewModels
{
public class Order02VM
{
public List<ActiveOrder02> ActiveOrders02 { get; set; }
}
public class ActiveOrder02
{
public decimal ID { get; set; }
public string Client { get; set; }
}
}
EDIT: What I'm after is by DisplayNameFor to present the name of column tableClient from SampleDbTable as a Header of column Client in the Index view.
Thank you!

Answer 1

Because model.ActiveOrders02 is of type List<ActiveOrder02>, not of type ActiveOrder02.
It looks like you just want to get the display meta-data of the property, not a value of a particular instance. There's a somewhat unintuitive way to do that:
#Html.DisplayNameFor(model => model.ActiveOrders02.First().Client)
Note the use of .First() on the list. One might intuitively think that this would be error-prone, because if the list is empty it would throw an exception. However, ASP.NET isn't actually going to use that to iterate over the list. This expression is being used by the framework to identify the property into which the framework will reflect to get meta-data about that property.
In most cases, putting something like that on a list would require that the list never be empty. In this particular case, however, it should work just fine.

Answer 2

From your code it is clear that ActiveOrders02 is a list of objects of type ActiveOrder02.
Client is a property in an element(ActiveOrder02) in ActiveOrders02. If you want the Client value in the first item in ActiveOrders02 you can go for
#Html.DisplayNameFor(model => model.ActiveOrders02[0].Client)
Of course you need to check if ActiveOrders02 is empty or not before doing this.

Answer 3

You instruct the view that #model is MVCDemo2.ViewModels.Order02VM, but in the controller you set o.ActiveOrders02 to List<MVCDemo2.ViewModels.Order02VM>:
o.ActiveOrders02 = resultSet02.Select(x => new ActiveOrder02
{
ID = x.tableId,
Client = x.tableClient
}).ToList(); // <--
Then you return View(o.ActiveOrders02.ToList());, essentially calling .ToList() on o.ActiveOrders02, which already is a List<MVCDemo2.ViewModels.Order02VM>.
So, you can:
return a single instance of Order02VM to the view rather than a list with one item, or...
return the list to the view, set the view's #model to List<MVCDemo2.ViewModels.Order02VM> and take the first Order02VM instance from the list (using .First(), list index 0, etc) and go from there.