public void CanGeneratePageLink()
        {
            //Arrange
            HtmlHelper myHelper = null;
            PagingInfo pagingInfo = new PagingInfo
            {
                CurrentPage = 2,
                TotalItems = 28,
                ItemPerPage = 10
            };
            Func<int, string> pageUrlDelegate = i => "Page" + i;

            //Act
            MvcHtmlString result = myHelper.PageLinks(pagingInfo, pageUrlDelegate);

            //Assert
            Assert.AreEqual(@"<a class=""btn btn-default"" href=""Page1"">1</a>"
                + @"<a class=""btn btn-default btn-primary selected"" href=""Page2"">2</a>"
                + @"<a class=""btn btn-default"" href=""Page3"">3</a>", result.ToString());
        }
        public static MvcHtmlString PageLinks(this HtmlHelper html,
                                              PagingInfo paginInfo,
                                              Func<int, string> pageUrl)
        {
            StringBuilder result = new StringBuilder();
            for (int i = 1; i <= paginInfo.TotalPages; i++)
            {
                TagBuilder tag = new TagBuilder("a");
                tag.MergeAttribute("href", pageUrl(i));
                tag.InnerHtml = i.ToString();
                if(i==paginInfo.CurrentPage)
                {
                    tag.AddCssClass("selected");
                    tag.AddCssClass("btn-defautl");
                }
                tag.AddCssClass("btn btn-default");
                result.Append(tag.ToString());
            }

            return MvcHtmlString.Create(result.ToString());
        }