问如何在mvc中从动态添加的textbox中保存多个数据库数据

EN

 public ActionResult Create([Bind(Include = "PurchaseInvoiceTable,PurchaseInvoiceDetailsTable,PaymentTerm")]InvoiceWrapper model)            
{
    try
    {

        if (ModelState.IsValid)
        {

            db.PurchaseInvoiceTables.Add(model.PurchaseInvoiceTable);                    
            db.SaveChanges();

            var PID = model.PurchaseInvoiceTable.PurchaseInvoiceID;
            model.PurchaseInvoiceDetailsTable.InvoiceID = PID;
            model.PaymentTerm.InvoiceID = PID;

            db.PurchaseInvoiceDetailsTables.Add(model.PurchaseInvoiceDetailsTable);
            db.PaymentTerms.Add(model.PaymentTerm);
            db.SaveChanges();

            return RedirectToAction("Index");
        }

        ViewBag.InvoiceID = new SelectList(db.PurchaseInvoiceTables, "PurchaseInvoiceID", "PurID", model.PurchaseInvoiceDetailsTable.InvoiceID);
        ViewBag.InvoiceID = new SelectList(db.PurchaseInvoiceTables, "PurchaseInvoiceID", "PurID", model.PaymentTerm.InvoiceID);             
        return View(model);
    }
    catch (DbEntityValidationException e)
    {
        //catch validation here
    }

}

using System;
using System.Collections.Generic;

namespace OnlineInvoiceSystem.Models
{
    public class InvoiceWrapper
    {
        public PurchaseInvoiceTable PurchaseInvoiceTable { get; set; }
        public PurchaseInvoiceDetailsTable PurchaseInvoiceDetailsTable { get; set; }
        public PaymentTerm PaymentTerm { get; set; }
    }
}

@model OnlineInvoiceSystem.Models.InvoiceWrapper 

@{ Layout = null; Layout = "~/Views/Shared/_Layout.cshtml"; } 

@using (Html.BeginForm()) { 

@Html.AntiForgeryToken()

<form>

  @Html.ValidationSummary(true, "", new { @class = "text-danger" })

  <h2>Product List</h2>

  <div class="panel panel-default product_wrapper">

    //dynamic added textbox will appear here

  </div>



  <button class="add_field_button btn btn-primary pull-right">Add More Fields</button>

  <div class="wrapper-payment-details">

    <tr style="background-color:black; color:white;" class="payment_term_wrapper">

      // here is the dynamic added payment terms textbox

    </tr>

  </div>

  <div class="form-group">
    <div>
      <input type="submit" value="Create" class="btn btn-primary pull-right" /> @Html.ActionLink("Back", "Index", null, new { @class = "btn btn-small btn-danger pull-right", @style = "margin-right:2%;" })
    </div>
  </div>

</form>
  }