ASP.NET MVC2 ORDER/ORDER LINE (Master/Detail) View - how to tie everything up

I've created this form: (code below)

Order Header
Order Item List
Order Payment List
Order Summary

I'm populating the list using Steve Sanderson method (jquery)

When I post the Form I get only the Header fields. How can I tie the 2 Lists Fields into the model (the Order inside the view model contain the enumeration for those list, and it is used to populate them. I need a way to send them back Plus the added rows of both list.

here is the page code:

   <h2>
        <%: Html.Label(Model.order.OrderID.ToString()) %></h2>
    <% using (Html.BeginForm("EditOrder", "Orders", FormMethod.Post, Model))
       {%>
    <%: Html.ValidationSummary(true)%>
    <fieldset>
        <legend>OrderDetails</legend>
        <div>
            <%: Html.Label("Order Date: ")%>
            <%: Html.TextBoxFor(o => o.order.OrderDate)%>
        </div>
        <p>
            <input type="submit" value="Save" />
        </p>
    </fieldset>
    <fieldset>
        <legend>Order Items:</legend>
        <div id="editorRows">
            <% foreach (var item in Model.order.ItemsInOrders)
               {
                   Html.RenderPartial("ItemEditorRow", item);
                   Html.Display("<br/>");
               }
            %>
        </div>
        <%= Html.ActionLink("Add...", "BlankItemRow", null, new { id = "addItem" }) %>
    </fieldset>
    <fieldset>
        <legend>Order Activities:</legend>
  <div id="ActivityRows">
        <% foreach (var item in Model.order.ActivityInOrders)
           {
               Html.RenderPartial("ActivityEditorRow", new TechRun.UI.Models.OrderActivityViewModel { acti开发者_如何学编程vity = item, activitiesList = Model.activities });
               Html.Display("<br/>");
           }
        %>
    </div>
        <%= Html.ActionLink("add...", "BlankActivityRow", null, new { id = "addItem2" })%>
    </fieldset>
    <fieldset>
        <legend>Order Summary:</legend>
    </fieldset>
    <%} %>

EDIT: UPDATED:

Here is the Partial Views:

<%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<TechRun.Shared.ItemsInOrder>" %>
<%@ Import Namespace="TechRun.UI.HtmlHelpers"%>
<div class="editorRow">
    <% using (Html.BeginCollectionItem("items"))
       { %>
        ID: <%: Html.TextBoxFor(x => x.ItemID)%>      
        ITEM: <%: Html.TextBoxFor(x => x.ItemDescription) %> 
        PRICE: <%: Html.TextBoxFor(x => x.CostOfItem, new { size = 4 }) %> 
        NUME: <%: Html.TextBoxFor(x => x.NumOfItems, new { size = 4 }) %>
        DatE: <%: Html.TextBoxFor(x => x.SupplyDate) %>
        Total: <%: Html.Label((Model.CostOfItem * Model.NumOfItems).ToString())%>
        <!-- This might be wrong -->
        <%: Html.HiddenFor(x=>x.TotalCost,Model.CostOfItem * Model.NumOfItems) %>
        <%: Html.HiddenFor(x=>x.OrderID, Model.OrderID) %>
    <% } %>

</div>
 <br />

And the other Row Generator:

<%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<TechRun.UI.Models.OrderActivityViewModel>" %>
<div class="ActivityRows">
    <% using (Html.BeginCollectionItem("activities"))
       { %>
    <% IEnumerable<SelectListItem> myActivityList = null;
           if(Model.activitiesList != null) 
           {
               myActivityList = Model.activitiesList.Select(o => new SelectListItem
                {
                    Text = o.ActivityID +
                     " - " + o.ActivityName + " Price: " + o.Cost + " TIME: " + o.ActivityTimeHours,
                    Value = o.ActivityID.ToString(),
                    Selected = (o.ActivityID == Model.activity.ActivityID)
                });
           }
           else return ; %>
    ID:
    <%: Html.DropDownListFor(x => x.activity.ActivityID, myActivityList)%>

    PRICE:
    <%: Html.TextBoxFor(x => x.activity.Cost, new { size = 4 })%>
    TIME:
    <%: Html.TextBoxFor(x => x.activity.TimeHours, new { size = 4 })%>
    NUM:
    <%: Html.TextBoxFor(x => x.activity.Items)%>
    TOTAL:
    <%: Html.Label((Model.activity.Items * Model.activity.Cost).ToString())%>
    <%: Html.HiddenFor(x => x.activity.Total, Model.activity.Cost * Model.activity.Items)%>
    <%: Html.HiddenFor(x => x.activity.OrderID, Model.activity.OrderID)%>
    <% } %>
</div>
<br />

And... the prefix Generating coding - copied from here

Your Html.BeginCollectionItem("items") lines need to be something like Html.BeginCollectionItem("order.ItemsInOrders")

where the parameter is the name of the property containing the items.

To be honest, I haven't tried this with a nested object. You may need to surface the list on the initial model first. Something like:

public xxxx order_ItemsInOrders
{
    get { return order.ItemsInOrders; }
    set { xxxx }  // may not bee needed
}

and then

<div id="editorRows">
    <% foreach (var item in Model.order_ItemsInOrders)
       {
           Html.RenderPartial("ItemEditorRow", item);
           Html.Display("<br/>");
       }
    %>
</div>

also ItemsInOrders or ItemsInOrders needs to be delared as a property.