AspNetCore pagination

_PagerPartial.cshtml

@* include Url.Current() extension method *@
@using MyProject.Web.Misc
@model MyProject.Web.Models.Pager

<!-- pager -->
@if (Model.EndPage > 1)
{
    <ul class="pagination">
        @if (Model.CurrentPage > 1)
        {
            <li>
                <a href="@Url.Current(new { pageNumber = 1 })">First</a>
            </li>
            <li>
                <a href="@Url.Current(new { pageNumber = Model.CurrentPage - 1 })">Previous</a>
            </li>
        }

        @for (int page = Model.StartPage; page <= Model.EndPage; page++)
        {
            <li class="@(page == Model.CurrentPage ? "active" : "")">
                <a href="@Url.Current(new { pageNumber = page })">@(page)</a>
            </li>    
        }

        @if (Model.CurrentPage < Model.TotalPages)
        {
            <li>
                <a href="@Url.Current(new { pageNumber = Model.CurrentPage + 1 })">Next</a>
            </li>
            <li>
                <a href="@Url.Current(new { pageNumber = Model.TotalPages })">Last</a>
            </li>
        }
    </ul>
}
<!-- /pager -->

Pager.cs

public class Pager
    {
        public Pager(int totalItems, int? page, int pageSize = 10)
        {
            // calculate total, start and end pages
            var totalPages = (int)Math.Ceiling((decimal)totalItems / (decimal)pageSize);
            var currentPage = page != null ? (int)page : 1;
            var startPage = currentPage - 5;
            var endPage = currentPage + 4;
            if (startPage <= 0)
            {
                endPage -= (startPage - 1);
                startPage = 1;
            }
            if (endPage > totalPages)
            {
                endPage = totalPages;
                if (endPage > 10)
                {
                    startPage = endPage - 9;
                }
            }

            TotalItems = totalItems;
            CurrentPage = currentPage;
            PageSize = pageSize;
            TotalPages = totalPages;
            StartPage = startPage;
            EndPage = endPage;
        }

        public int TotalItems { get; private set; }
        public int CurrentPage { get; private set; }
        public int PageSize { get; private set; }
        public int TotalPages { get; private set; }
        public int StartPage { get; private set; }
        public int EndPage { get; private set; }
    }

UrlHelperExtensions.cs

public static class UrlHelperExtensions
    {
        /// <summary>
        /// Get current URL with some substituted values. Preserves query string.
        /// </summary>
        /// <param name="helper"></param>
        /// <param name="substitutes"></param>
        /// <returns></returns>
        public static string Current(this IUrlHelper helper, object substitutes)
        {
            RouteValueDictionary routeData = new RouteValueDictionary(helper.ActionContext.RouteData.Values);
            IQueryCollection queryString = helper.ActionContext.HttpContext.Request.Query;

            //add query string parameters to the route data
            foreach (var param in queryString)
            {
                if (!string.IsNullOrEmpty(queryString[param.Key]))
                {
                    //rd[param.Key] = qs[param.Value]; // does not assign the values!
                    routeData.Add(param.Key, param.Value);
                }
            }

            // override parameters we're changing in the route data
            //The unmatched parameters will be added as query string.
            foreach (PropertyDescriptor property in TypeDescriptor.GetProperties(substitutes.GetType()))
            {
                var value = property.GetValue(substitutes);
                if (string.IsNullOrEmpty(value.ToString()))
                {
                    routeData.Remove(property.Name);
                }
                else
                {
                    routeData[property.Name] = value;
                }
            }

            string url = helper.RouteUrl(routeData);
            return url;
        }
    }

UsageInView.cshtml

@model SomeModelWithPagerProperty

@* current page items *@
  
@{ Html.RenderPartial("_PagerPartial", Model.Pager); }