Post viewmodel with List<T> to controller action method

Question

I know there are a lot of posts out there regarding this, most of which I have read and tried all morning but still can't get it working.

I have a view model as such:

namespace GrantTracker.ViewModels
{
    public class CoverPageViewModel
    {
        public List<Compliance> Compliances { get; set; }
    }
}

I have a partial view that uses the view model:

<%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<GrantTracker.ViewModels.CoverPageViewModel>" %>

<%
for (var i = 0; i < Model.Compliances.Count; i++)
{ %>               
        <%=Html.HiddenFor(x => x.Compliances[i].ComplianceId) %>
        <%=Html.TextBoxFor(x => x.Compliances[i].ComplianceName) %>                 

<% } %>

This properly displays the text boxes and their values:

The generated source looks ok to me:

<input id="Compliances_0__ComplianceId" name="Compliances[0].ComplianceId" type="hidden" value="1" />
<input id="Compliances_0__ComplianceName" name="Compliances[0].ComplianceName" type="text" value="Human Subjects" />                 

<input id="Compliances_1__ComplianceId" name="Compliances[1].ComplianceId" type="hidden" value="2" />
<input id="Compliances_1__ComplianceName" name="Compliances[1].ComplianceName" type="text" value="Vertebrate Animals" />                 

<input id="Compliances_2__ComplianceId" name="Compliances[2].ComplianceId" type="hidden" value="3" />
<input id="Compliances_2__ComplianceName" name="Compliances[2].ComplianceName" type="text" value="Hazardous Substances" />  

When I submit the page the textbox properties are as far as I can tell properly posted:

Compliances[0].ComplianceId:1
Compliances[0].ComplianceName:Human Subjects
Compliances[1].ComplianceId:2
Compliances[1].ComplianceName:Vertebrate Animals
Compliances[2].ComplianceId:3
Compliances[2].ComplianceName:Hazardous Substances

However, the values are all gone when accessed in the controller action

[HttpPost]
public ActionResult SaveCoverPage(CoverPageViewModel coverPageViewModel)
{
    return Content(coverPageViewModel.Compliances[0].ComplianceId.ToString());
}

The debugger shows that it knows it should contain three Compliance objects.
However, when drilled down none of them have their values:

Any help with this would be greatly appreciated. I am really stuck on this.

Answer 1

Change your Compliance class as below.

public class Compliance
{
    public int ComplianceId { get; set; }
    public string ComplianceName { get; set; }
}

You should define properties correctly.