PagerTagHelper.cs

using System;
using System.Text;
using Microsoft.AspNet.Mvc.Rendering;
using Microsoft.AspNet.Razor.TagHelpers;
using Microsoft.Extensions.WebEncoders;

namespace WebInterface.TagHelpers
{
    [HtmlTargetElement("pager", Attributes = "total-items, items-per-page")]
    public class PagerTagHelper : TagHelper
    {
        public int TotalItems { get; set; }
        public int ItemsPerPage { get; set; }
        public override void Process(TagHelperContext context, TagHelperOutput output)
        {
            output.TagName = "div";
            output.PreContent.SetHtmlContent(""); 

            var items = new StringBuilder();
            int totalPages = (int) Math.Ceiling((double) TotalItems/ItemsPerPage);
            for (var i = 1; i <= totalPages; i++)
            {
                var li = new TagBuilder("li");

                var a = new TagBuilder("a");
                a.MergeAttribute("href", "javascript:void(0)");
                a.MergeAttribute("title", string.Format("Click to go to page {0}", i));
                a.InnerHtml.AppendHtml(i.ToString());
                if (i == 1)
                {
                    a.AddCssClass("active");
                }

                li.InnerHtml.Append(a);
                var writer = new System.IO.StringWriter();
                li.WriteTo(writer, new HtmlEncoder());
                var s = writer.ToString();
                items.AppendLine(s);
            }
            output.Content.SetHtmlContent(items.ToString());
            output.PostContent.SetHtmlContent(""); 
            output.Attributes.Clear();
            output.Attributes.Add("class", "pager");
        }
    }
}