Question

I am new to MVC. i have problem to pass data from view to controller.

This application is for ordering Shirts. I have different types like T-shirts, Casual shirts and Formal Shirts. In a single order, I would like to place order for 2 T-shirts, 3 Casual shirts and 5 Formal Shirts. I am able to edit single value, i.e. either of them, in one order. The problem I am facing is with ordering multiple types of shirts in one order.

public class Shirt    
{
   //[Key]
   public int ShirtId{ get; set; }
   public string ShirtName{ get; set; } // This is an read-only field    
}

public class Order
{
    public int ShirtId { get; set; }
    public virtual Shirt Shirt { get; set; } // a reference to Shirt
    public int Quantity { get; set; } 
    public int OrderId { get; set; }
}

I have a view that is strongly typed with my viewmodel “Order”. Initially I passed data from my Controller to View using

     [HttpGet]
    public ActionResult Index()
    {
       OrdersList();
       return View(db.Order.ToList());
    }

Here OrdersList is a function that interacts with database and gets a list of Orders

   void OrdersList()
   {
     ViewBag.OrdersLsit= from f in db.Shirt
                            orderby f.ShirtName
                            select f;
   }

I am getting data back to Controller using,

    [HttpPost]
    public ActionResult Index(List<Order> order)
    {
        Order newOrder = new Order();
        for (int i = 0; i < order.Count; i++)
        {
            newOrder.Quantity = order.ElementAt(i).Quantity;
            if (ModelState.IsValid)
            {
                db.Entry(newOrder).State = EntityState.Modified;

                db.SaveChanges();
            }
        }
    }

My problem is List order is passed as Null. If I do
public ActionResult Index(Order order) in HttpPost, I am getting only the first item(in this case a T shirt is getting updated in database).

In Index.cshtml, I am doing something like this

  <legend>Order Shirts</legend>
         <table>
            <tr>
                @{List<Order> orderList = new List<Order>(); }
                @foreach (Order ord in ViewBag.OrderList)
                {
                    <td>
                    @Html.DisplayFor(model => ord.Shirt.Shirtname)
                    </td>
                    orderList.Add(ord);
                }
            </tr>

            <tr>
                @for (int i = 0; i < orderList.Count; i++)
                {
                    <td class = "editorClass">
                            @Html.HiddenFor(model => orderList.ElementAt(i).Shirt.ShirtId)
                            @Html.HiddenFor(model => orderList.ElementAt(i).OrderId)
                            @Html.ValidationSummary(true)
 @Html.HiddenFor(model => orderList.ElementAt(i).ShirtId)                                
                            @Html.EditorFor(model => orderList.ElementAt(i).Quantity)
                            @Html.ValidationMessageFor(model => orderList.ElementAt(i).Quantity)
                    </td>
                }
            </tr>
        </table>
    </fieldset>
   <p>
       <input id = "btnSubmit" type="submit" value="Save Order" /> 
    </p>
    <div>
        @Html.ActionLink("Back to List", "Index")
    </div>

I am new to MVC and this is my first application. Any constructive comments and suggestions are appreciated.
Thanks

Answer 1

I don’t understand why you are creating orderList instead the view, actually you have to pass that from the controller and strongly type the view to List<Order>.

Instead of using this,

@Html.EditorFor(model => orderList.ElementAt(i).Quantity)

You could try (if you strongly type the view to List<Order>),

@Html.EditorFor(m => m[i].Quantity)

If the view is not strongly typed to List<Order> you could try this,

@Html.EditorFor(m => orderList[i].Quantity)

But in this case you have to change the action as below,

[HttpPost]
public ActionResult Index([Bind(Prefix="orderList")]List<Order> order)
{
}

The reason is I’m not sure whether the ElementAt(i) generate the names properly for fields, so try index approach!