Configure list of items to send to server - asp.net-mvc-4

Question

I want the user to be able to construct a list of items client-side in a form and then send the entire list to the server when the form is submitted.
Each item has several properties that can be set. For example, here's an Order model:
class Order
{
int Id;
string Description;
Guid UserId;
string Product;
}
The user should be able to add and configure as many orders as they want before submitting the form.
I thought I could do this with the Telerik grid using InCell editing. Unfortunately, the list of available options for each field will change based on the value chosen for other fields. I couldn't make this work with InCell editing because I couldn't access the other ui elements from my javascript event handlers.
I also tried to do this with normal InLine editing, but the only item returned is the new Order to be added. I couldn't access the GridModel to add the new Order. I don't want to persist the Order list until the user is done editing.
Any help would be greatly appreciated.
EDIT: If I go with the solution of making my own list, I have this problem with cascading comboboxes. Each combobox has a name like "UserId_0" based on what index it is in the list.
But now how do I get the downstream list?
Here's my two comboboxes:
<td>
#(Html.Telerik().ComboBox()
.Name("UserId_" + i.ToString())
.BindTo(new SelectList(Model.UserIds, "Id", "Name"))
.Placeholder("Select UserId...")
.AutoFill(true)
.CascadeTo("Product_" + i.ToString())
.SelectedIndex(0))
</td>
<td>
#(Html.Telerik().ComboBox()
.Name("Product_" + i.ToString())
.AutoFill(true)
.DataBinding(binding => binding.Ajax().Select("GetProducts", "Order"))
.Placeholder("Select Product...")
.SelectedIndex(0))
</td>
And my Controller method looks like this. It's hacky as hell, but how do I access the value otherwise?
public JsonResult GetProducts(Guid? UserId)
{
// Hack!
ValueProviderResult userResult = ValueProvider.GetValue("UserId");
for (int i=0; i < 10; i++)
{
userResult = ValueProvider.GetValue("UserId_" + i);
if (userResult != null)
{
break;
}
}
if (userResult != null)
{
// Get list of products based on value
return Json(new SelectList(productList, "Id", "Name"));
}
else
{
return Json(null);
}
}

Answer 1

Do not waste your time to achieve this with the some widget - better check how to send collection of items to the server and implement your own form with checkboxes or so.
If you want to go with some of the widgets - you can try the Grid in a way similar to this demo.