.Net 6 MVC - ViewModel - Displaying Second Property in a View

Question

Premise:

I'm trying to use a very simplified .net 6 MVC project to gain understanding of how to code ViewModels.

Thumbnail of Project

Models A B C (Joining Class)

ViewModel AB

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**GitHub **

Environment: Net Core 6 MVC, Visual Studio Community 2022 (64 bit), WIndows 11

Please: whenever possible, provide help in the form of actual code - preferably changes to the code I've provided (a fair amount of time and effort goes into providing this code as the premise for the question) - or in example(s) of code you provide, in either case, in the format / syntax the code needs to be in to make the project. Abstraction, more often than not, obfuscates the answer.

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Question

Why does data from the first property display but not from the second property? How do I change the controller action method code (below) to also display data from the second property?

Controller Action Method displays successfully as pictured (above)

        //GET: AB
        public IActionResult AB2()
        {
            //define a variable to store the return data.
            var ab2 = new List<AB>();
            //query A and B table, 
            var Alist = _context.A.ToList();
            var Blist = _context.B.ToList();
            //use foreach statement to filter data. And Add A and B to the ab list.
            foreach (var item in Alist)
            {
                var newab = new AB()
                {
                    A = item
                };
                //add the new item into the list.
                ab2.Add(newab);
            }
            return View(ab2); // return the list to the view page.
        }

**Full Code **

Models

A

    namespace ViewModel.Models
    {
    public class A
        {
        public int Id { get; set; }

        public string? One { get; set; }

        public string? Two { get; set; }

        public string? Three { get; set; }

        public IEnumerable<C>? C { get; set; }

        }
   }

B

namespace ViewModel.Models
{
    public class B
    {
        public int Id { get; set; }

        public string? One { get; set; }

        public string? Two { get; set; }

        public string? Three { get; set; }

        public IEnumerable<C>? C { get; set; }
    }
}

C

using System.Security.Cryptography.Xml;

namespace ViewModel.Models
{
    public class C
    {
        public int Id { get; set; }

        public int AId { get; set; }

        public int BId { get; set; }

        // _______________________________________

        public A? A { get; set; }
        public B? B { get; set; }
    }
}

Context

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.EntityFrameworkCore;
using ViewModel.Models;

namespace ViewModel.Data
{
    public class ViewModelContext : DbContext
    {
        public ViewModelContext (DbContextOptions<ViewModelContext> options)
            : base(options)
        {
        }

        public DbSet<ViewModel.Models.A> A { get; set; } = default!;

        public DbSet<ViewModel.Models.B>? B { get; set; }

        public DbSet<ViewModel.Models.C>? C { get; set; }
    }
}

ViewModel

using System.Security.Cryptography.Xml;

namespace ViewModel.Models.View
{
    public class AB
    {
        public A? A { get; set; }

        public B? B { get; set; }
    }
}

View

@model IEnumerable<ViewModel.Models.View.AB>

@{
    ViewData["AB2"] = "AB2";
}

<h1>AB2</h1>

<p>
    <a asp-action="Create">Create New</a>
</p>
<table class="table">
    <thead>
        <tr>
            <th>
                Property Set A, Property @Html.DisplayNameFor(model => model.A.One)
            </th>
            <th>
                Property Set B, Property @Html.DisplayNameFor(model => model.B.One)
            </th>
            <th></th>
        </tr>
    </thead>
    <tbody>
@foreach (var item in Model) {
        <tr>
            <td>
                @Html.DisplayFor(modelItem => item.A.One)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.B.One)
            </td>
            <td>
                <a asp-action="Edit" asp-route-id="@item.A.Id">Edit</a> |
                <a asp-action="Details" asp-route-id="@item.A.Id">Details</a> |
                <a asp-action="Delete" asp-route-id="@item.A.Id">Delete</a>
            </td>
        </tr>
}
    </tbody>
</table>

I created simplified project to use as a premise for this question. I have a working view derived through a viewmodel that includes a property from each of two classes. My question is now about a second view, coded in the controller differently from the first that displays a property from one class. I'm trying to get a second property from a second class to display.

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I've tried a few changes to the controller action method code. Both failed:

        //GET: AB
    public IActionResult AB2()
    {
        //define a variable to store the return data.
        var ab2 = new List<AB>();
        //query A and B table, 
        var Alist = _context.A.ToList();
        var Blist = _context.B.ToList();
        //use foreach statement to filter data. And Add A and B to the ab list.
        foreach (var item in Alist)
        {
            var newab = new AB()
            {
                A = item
              //B = item                  **2nd change: did not work**
            };
            //add the new item into the list.
            ab2.Add(newab);
        }

        //foreach (var item in Blist)    **1st change: did not work**
        //{
        //    var newab = new AB()
        //    {
        //        B = item
        //    };
        //    //add the new item into the list.
        //    ab2.Add(newab);
        //}

        return View(ab2); // return the list to the view page.
    }