How to sort using repository pattern in ASP.NET core?

Question

I have been having problems trying to implementing a sorting function for my project using the repository pattern. All the tutorials I have seen uses sorting via a database while I am simply just trying to sort some of my hard-coded objects that exist in my repository.

Object class

public class Object
{
     [HiddenInput]
     public int ObjectId { get: set; }
     public string Name { get; set; }
}

IObjectRepository interface

public interface IObjectRepository
{
     IEnumerable<Object> GetAllObjects();
     //public List<Object> ObjectSort(string sortOrder);
}

ObjectRepository class

public class ObjectRepository : IObjectRepository
{
     private List<Object> _objectList;
     public ObjectRepository()
     {
          _objectList = new List<Object>()
          {
               new Object { ObjectId = 1, Name = "Math"},
               new Object { ObjectId = 2, Name = "Science"}
          };
     }
     public IEnumerable<Object> GetAllObjects()
     {
          return _objectList;
     }
     //public List<Object> ObjectSort(string sortOrder) method
}

Home Controller

public class HomeController : Controller
{
     private readonly IObjectRepository _objectRepository;
     
     public HomeController(IObjectRepository objectRepository)
     {
          _objectRepository = objectRepository;
     }
     public IActionResult Index()
     {
          return View();
     }
     public IActionResult ObjectList()
     {
          return View(_objectRepository.GetAllObjects());
     }
     public IActionResult Sort(string sortOrder)
     {
          ViewData["NameSortParm"] = String.IsNullorEmpty(sortOrder) ? "name_desc" : "";
          var objects = from s in _objectRepository.GetAllObjects()
                        select s;
          switch (sortOrder)
          {
               case "name_desc":
                    objects = objects.OrderByDescending(s => s.Name);
                    break;
               default:
                    objects = objects.OrderBy(s => s.Name);
                    break;
          }
          return View("ObjectList");
     }
}

The commented-out lines indicate that I am aware that something should go there but the tutorials I watched did not have anything in those models. I am attempting to sort by clicking on the table header for Name in my ObjectList View which more or less looks like this.

<th>
    <a asp-action="ObjectList" asp-route-sortOrder="@ViewData["NameSortParm"]">@Html.DisplayNameFor(model => model.Name)</a>
</th>

I am stuck and unsure about what to do. The farthest I have gotten is clicking on the table header for Name, but the page is unable to display the objects that I am trying to sort. Any help would be much appreciated.

Answer 1

You just need one ObjectList action like below:

public IActionResult ObjectList(string sortOrder)
{
    ViewData["NameSortParm"] = String.IsNullOrEmpty(sortOrder) ? "name_desc" : "";
    var objects = from s in _objectRepository.GetAllObjects()
                    select s;
    switch (sortOrder)
    {
        case "name_desc":
            objects = objects.OrderByDescending(s => s.Name);
            break;
        default:
            objects = objects.OrderBy(s => s.Name);
            break;
    }
    return View(objects);
}

View:

@model IEnumerable<MyObject>
@{
    ViewData["Title"] = "ObjectList";
}

<h1>ObjectList</h1>

<table>
    <thead>
        <tr>
            <th>
                @Html.DisplayNameFor(model => model.ObjectId)
            </th>
            <th>
                <a asp-action="ObjectList" asp-route-sortOrder="@ViewData["NameSortParm"]">@Html.DisplayNameFor(model => model.Name)</a>
            </th>
        </tr>
    </thead>
    <tbody>
        @foreach (var item in Model)
        {
        <tr>
            <td>
                @Html.DisplayFor(m => item.ObjectId)
            </td>
            <td>
                @Html.DisplayFor(m => item.Name)
            </td>
        </tr>
        }

    </tbody>
</table>

Result: