I'm busy with an ASP.NET Core MVC application, and I'm trying to populate a drop down list. I've created a view model and I have added a method to my StoresController that returns a list of stores that I want to display in a dropdown. I've been working off some online tutorials as I'm very new to asp.

View model:

public class StoreListViewModel
{
    public List StoreList { get; set; } = new List();
}

public class StoreList
{
    public string StoreId { get; set; } = null!;
    public string StoreName { get; set; } = null!;
}

StoresController:

public IActionResult LoadStoreList()
{
    if (ModelState.IsValid)
    {
        var storeList = new StoreListViewModel().StoreList.Select
                        (x => new SelectListItem { Value = x.StoreId, Text = x.StoreName }).ToList();
        ViewBag.Stores = storeList;
    }

    return NotFound();
}

I'm trying to use ViewBag to call my LoadStoreList() method.

When I load my page I get the following error

Value cannot be null. (Parameter 'items')

The page I need the dropdown list on is my CreateUser.cshtml which is bound to my UserModel and has a UsersController. The method I have created for listing the stores is in my StoresController which is bound to my StoresModel. So I'm not sure if that's causing the issue.

I've been battling with this for days, if someone could help me get this working or show me a better method, that would be great.

*Edit

The UserIndex() method is the first method that fires when my users page opens, do I call the LoadStoreList() method from there ?

UserController

public async Task UsersIndex()
{
      return _context.UsersView != null ? 
                  View(await _context.UsersView.ToListAsync()) :
                  Problem("Entity set 'ApplicationDbContext.Users'  is null.");
}