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POASP MVC View posts null to Controller
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  1. POASP MVC View posts null to Controller
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    copied!<p>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.</p> <p>Given the following View:</p> <pre><code>@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 &lt; Model.AvailableStaffMembers.Count; i++) { var staff = Model.AvailableStaffMembers[i]; &lt;tr&gt; &lt;td&gt;@Html.HiddenFor(model =&gt; staff.ID)@Html.ValueFor(model =&gt; staff.ID)&lt;/td&gt; &lt;td&gt; @Html.DropDownListFor( model =&gt; model.SalutationID, Model.AvailableSalutations.Select(option =&gt; new SelectListItem { Text = option.Desc.ToString(), Value = option.ID.ToString(), Selected = (option.ID.ToString() == staff.SalutationID.ToString()) } ), "Choose...") &lt;/td&gt; &lt;td&gt;@Html.EditorFor(model =&gt; staff.FName)&lt;/td&gt; &lt;td&gt;@Html.EditorFor(model =&gt; staff.LName)&lt;/td&gt; &lt;td&gt;@Html.EditorFor(model =&gt; staff.Active)&lt;/td&gt; &lt;td&gt;&lt;a href="/Settings/DeleteStaff?id=@Html.ValueFor(model =&gt; staff.ID)"&gt;Delete&lt;/a&gt;&lt;/td&gt; &lt;/tr&gt; } </code></pre> <p>and the following Controller:</p> <pre><code> 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&lt;Prm_Salutation&gt;(); 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&lt;Prm_Staff&gt;(); 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&lt;&gt; { var tbl = db.Prm_Staffs.Where(a =&gt; 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" }); } </code></pre> <p>And, for good measure, the ViewModel itself:</p> <pre><code> 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&lt;Prm_Salutation&gt; AvailableSalutations { get; set; } public List&lt;Prm_Staff&gt; AvailableStaffMembers { get; set; } public Staff_Salutation_VM() { } } </code></pre> <p>When triggered, no form values populate the ActionResult, resulting in a <code>Object reference not set to an instance of an object.</code> exception being thrown when the <code>foreach (var formData in list)</code> line is reached. Debugging shows <code>list</code> as being null. How can this be so? Or rather, what am I doing wrong?</p> <p>EDIT: the <code>list</code> variable in my POST <code>ActionResult</code> 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?</p>
 

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