ASP MVC View posts null to Controller

I am a beginner in ASP MVC, and, after a lot of help from SO, am progressing through ViewModels. Using a ViewModel however, I have encountered the following error.

Given the following View:

@model November.ViewModels.Staff_Salutation_VM

//...

using (Html.BeginForm("UpdateStaff", "Settings", FormMethod.Post, 
    new { @class = "clearfix parameter-form update-parameter update-staff", enctype = "multipart/form-data" }))
{
    @Html.AntiForgeryToken()
    @Html.ValidationSummary(true)

    //...       

    @for (int i = 0; i < Model.AvailableStaffMembers.Count; i++)
    {
        var staff = Model.AvailableStaffMembers[i];
        <tr>               
            <td>@Html.HiddenFor(model => staff.ID)@Html.ValueFor(model => staff.ID)</td>
            <td>
                @Html.DropDownListFor(  
                    model => model.SalutationID, Model.AvailableSalutations.Select(option => new SelectListItem 
                        {
                            Text = option.Desc.ToString(),
                            Value = option.ID.ToString(),
                            Selected = (option.ID.ToString() == staff.SalutationID.ToString())
                        }
                    ), 
                "Choose...")
            </td>
            <td>@Html.EditorFor(model => staff.FName)</td>
            <td>@Html.EditorFor(model => staff.LName)</td>
            <td>@Html.EditorFor(model => staff.Active)</td>
            <td><a href="/Settings/[email protected](model => staff.ID)">Delete</a></td>
        </tr>
    }

and the following Controller:

 using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Web;
 using System.Web.Mvc;
 using November.Models;
 using November.ViewModels;
 using November.DAL;   

 //...

 //GET
 var staffCreateViewModel = new Staff_Salutation_VM();

 staffCreateViewModel.AvailableSalutations = new List<Prm_Salutation>();
 var activeSalts = (from a in db.Prm_Salutations
                     where a.Active == true
                     orderby a.Desc ascending
                     select a);
 staffCreateViewModel.AvailableSalutations = activeSalts.ToList();

 staffCreateViewModel.AvailableStaffMembers = new List<Prm_Staff>();
 var activeStaff = (from a in db.Prm_Staffs
                     where a.Active == true
                     orderby a.LName ascending
                     select a);
 staffCreateViewModel.AvailableStaffMembers = activeStaff.ToList();

 return View("StaffMembers", staffCreateViewModel);



 //POST
 public ActionResult UpdateStaff(Staff_Salutation_VM list)
 {
      if (ModelState.IsValid)
      {
           foreach (var formData in list) //no longer works due to dropping List<>
           {
                var tbl = db.Prm_Staffs.Where(a => a.ID.Equals(formData.ID)).FirstOrDefault();
                if (tbl != null)
                {
                     var Prm_StaffModel = new Prm_Staff();

                     Prm_StaffModel.SalutationID = formData.SalutationID;
                     Prm_StaffModel.FName = formData.FName;
                     Prm_StaffModel.LName = formData.LName;
                     Prm_StaffModel.Active = formData.Active;
                }
           }
           db.SaveChanges();
           ViewBag.UpdateRtrn = "Successfully Updated.";
           return RedirectToAction("Parameters", new { param = "Staff Members" });
      }
      else
           {
                ViewBag.UpdateRtrn = "Failed ! Please try again.";
                return RedirectToAction("Parameters", new { param = "Staff Members" });
           }
      }
      return RedirectToAction("Parameters", new { param = "Staff Members" });
 }

And, for good measure, the ViewModel itself:

 public class Staff_Salutation_VM
 {
      public int ID { get; set; }
      public int SalutationID { get; set; }
      public string FName { get; set; }
      public string LName { get; set; }
      public bool Active { get; set; }

      public List<Prm_Salutation> AvailableSalutations { get; set; }
      public List<Prm_Staff> AvailableStaffMembers { get; set; }

      public Staff_Salutation_VM() { }        
 }

When triggered, no form values populate the ActionResult, resulting in a Object reference not set to an instance of an object. exception being thrown when the foreach (var formData in list) line is reached. Debugging shows list as being null. How can this be so? Or rather, what am I doing wrong?

EDIT: the list variable in my POST ActionResult is now getting data - or at least, is showing the various types in the class when debugged. How do I then iterate through it to save that data in the appropriate rows of the DB?