Dropdownlist in C# & ASP.NET Core

Question

I want to create a dropdown with C#, ASP.NET Core that will be displayed in the view and get the information of the dropdown list from the database and display it in the view. How can I do this?

While the selectListItem in the space there is a name that is obsolete.

public class AddUserRoleDto
{
   public string Id { get; set; }
   public string Role { get; set; }
   public List<SelectListItem> Roles{ get; set; }
}

public IActionResult AddUserRole(string Id)
{
   var role = new List<SelectListItem>(
        _roleManager.Roles.Select(p => new SelectListItem
                     {
                         Text = p.Name,
                         Value = p.Name
                     }).ToList());
  


   return View(new AddUserRoleDto
                   {
                       Id = Id,
                       Roles = role,
                   });
}

Answer 1

I want to create a dropdown with C#, ASP.NET Core that will be displayed in the view

In the AddUserRole, you can use ViewBag to pass the SelectList to the view:

public IActionResult AddUserRole(string Id)
{
     //do your staff
     ViewBag.Roles = new SelectList(_roleManager.Roles, "Name", "Name");
}

Then in the view use asp-items :

<select name="Roles" class="form-control" asp-items="@ViewBag.Roles"></select>