I have written an action for a Partial view where I am calling a select list, and have passed same in the _Layout.cshtml.
The dropdown loads on Home/Index action, but the complete website stops working when access any other Action and Controller method.

Home Contoller Action

    public IActionResult Index()
{
    ViewBag.Proj = new SelectList(db.Projects.ToList(), "ProjectId", "ProjectName");
    return View();
}

_Layout.cshtml

@await Html.PartialAsync("~/Views/Home/_partial.cshtml")

I am trying to achieve to get select list and pass it in a form which opens on a button click and which is placed on header menu.