Pagination in C# Asp.net Core

CategoryController.cs

  public IActionResult Index(int pageNumber = 1, int pageSize = 10)
  {
      IEnumerable<Category> categoryList = _db.Categories.ToList();
      if (pageNumber < 1) pageNumber = 1;
      int totalItems = categoryList.Count();

      var pager = new Pager(totalItems, pageNumber, pageSize);
      int recSkip = (pageNumber - 1) * pageSize;
      var data = categoryList.Skip(recSkip).Take(pager.PageSize).ToList();
      this.ViewBag.Pager = pager;
      return View(data);
  }

Index.cshtml

int pageNumber = 0;
if (ViewBag.Pager != null)
{
    pager = ViewBag.Pager;
    pageNumber = pager.CurrentPage;
}
<--HTML-->
   @if (pager.TotalPages > 0)
 {
     <ul class="pagination pagination-sm mb-0">
         <li class="page-item @(pager.CurrentPage > 1 ? "":"disabled")">
             <a class="page-link" asp-controller="Category" asp-action="Index" , asp-route-pageNumber="@(pager.CurrentPage -1 )">&laquo;</a>
         </li>
         @for (var pge = pager.StartPage; pge <= pager.EndPage; pge++)
         {
             <li class="page-item @(pge == pager.CurrentPage ? "active":"")">
                 <a class="page-link" asp-controller="Category" asp-action="Index" asp-route-pageNumber="@pge">@pge</a>
             </li>
         }
         <li class="page-item @(pager.CurrentPage < pager.TotalPages ?"":"disabled")">
             <a class="page-link" asp-controller="Category" asp-action="Index" asp-route-pageNumber="@(pager.CurrentPage+1)">&raquo;</a>
         </li>
     </ul>
 }
<--HTML-->

Pager.cs

namespace bulkyBook.Models
{
    public class Pager
    {
        public int TotalItems { get; set; }
        public int CurrentPage { get; set; }
        public int PageSize { get; set; }
        public int TotalPages { get; set; }
        public int StartPage { get; set; }
        public int EndPage { get; set; }

        public Pager() { }

        public Pager(int totalItems, int page, int pageSize)
        {
            int totalPages = (int)Math.Ceiling((decimal)totalItems / (decimal)pageSize);
            int currentPage = page;
            int startPage = currentPage - 5;
            int endPage = currentPage + 5;

            if (startPage <= 0)
            {
                endPage = endPage - (startPage - 1);
                startPage = 1;
            }
            if (endPage > totalPages)
            {
                endPage = totalPages;
                if (endPage > 10)
                {
                    startPage = endPage - 10;
                }
            }
            TotalItems = totalItems;
            CurrentPage = currentPage;
            PageSize = pageSize;
            TotalPages = totalPages;
            StartPage = startPage;
            EndPage = endPage;
        }
    }
}