Passing a List as @Html.Hidden and the list is being deleted

I am having an issue sending through a list from a form to a controller to work with and edit. It just destroys the list and passes through just one empty string. I need the list to maintain so that i can add to it in the controller.

The view looks like this:

@using (Html.BeginForm("AddToBasket", "Home", FormMethod.Post))
        {
            @Html.Hidden("product", product.Product)
            @Html.Hidden("basketItems", Model.BasketItems)

            <h3>@product.Product (£@product.Price)</h3>
            <div class="menu-item-quantity">
                <h4>Quanitity: @Html.TextBox("quantity", 0, new { @class = "form-control-quantity" })</h4>
            </div>
            <input class="btn btn-lg" type="submit" value="Add to basket" />
        }

The controller:

public ActionResult AddToBasket(string product, int quantity, List<string>basketItems)
        {   
            var products = new GetProductsList<ProductLookup>().Query().ToList();

            var Result = new BuyViewModel
            {
                Products = products,
                BasketItems = basketItems.ToList()
            };

            return View("Buy", Result);
        }

and the model:

public class BuyViewModel
    {
        public IList<ProductLookup> Products { get; set; }

        public List<string> BasketItems { get; set; }
    }

How would i get that list through to the controller in one piece??

Instead of returning one item, you're looking for returning a list.

One way to do that is returning an array of form elements with the same name, so the controller can stitch that back into a list.

Here's an example:

Instead of:

@Html.Hidden("basketItems", Model.BasketItems)

Add this:

for (int i = 0; i < Model.BasketItems.Count; i++)
{
    @Html.HiddenFor(m => m.BasketItems[i])
}

This will generate the following html:

<input type="hidden" name="basketItems[0]" value="item 1" />
<input type="hidden" name="basketItems[1]" value="item 2" />

(maybe you don't need the @ in the @Html, but I haven't checked that)

update I created a test project:

TestViewModel.cs

using System;
using System.Collections.Generic;

namespace WebApplication1.Models
{
    public class TestViewModel
    {
        public string Name { get; set; }
        public List<String> Items { get; set; }
    }
}

HomeController.cs

using System.Collections.Generic;
using System.Web.Mvc;
using WebApplication1.Models;

namespace WebApplication1.Controllers
{
    public class HomeController : Controller
    {
        public ActionResult Index()
        {
            var viewModel = new TestViewModel {
                Name = "Test name",
                Items = new List<string> { "item 1" , "item 2" }
            };


            return View(viewModel);
        }

        [HttpPost]
        public ActionResult Index(string name, List<string> items)
        {
            var viewModel = new TestViewModel
            {
                Name = name,
                Items = items
            };
            return View(viewModel);
        }

    }
}

Index.cshtml

@model WebApplication1.Models.TestViewModel
@{
    ViewBag.Title = "Home Page";
}

@using (Html.BeginForm("Index", "Home", FormMethod.Post))
{

    for (int i = 0; i < Model.Items.Count; i++)
    {
        @Html.HiddenFor(m => m.Items[i])
    }


    <div class="">
        @Html.TextBoxFor(m => m.Name)
    </div>


    <input type="submit" value="save" />
}

When I click save, the form is displayed again but now with the values from the previous form