public Pagination(IPagingContextAspect pagingContext, IPagedResultsAspect totalResults)
{
this.Pages = new List <Page>();
if (pagingContext == null)
{
return;
}
if (totalResults == null || totalResults.ResultsTotal <= 0)
{
return;
}
var totalNumberPages = TotalNumberOfPages(totalResults.ResultsTotal, pagingContext.PageSize.Value);
SetPages(pagingContext, totalNumberPages);
HasPreviousPage = pagingContext.PageNumber.Value > 1;
HasNextPage = pagingContext.PageNumber.Value < totalNumberPages;
PreviousPageLink =
pagingContext.AsNameValueCollection()
.SetKey(Constants.SearchContext.Keys.PageNumber, pagingContext.PageNumber.Value - 1)
.ToQueryString(true);
NextPageLink =
pagingContext.AsNameValueCollection()
.SetKey(Constants.SearchContext.Keys.PageNumber, pagingContext.PageNumber.Value + 1)
.ToQueryString(true);
}
private void SetPages(IPagingContextAspect pagingContext, int totalNumberPages)
{
if (totalNumberPages == 0)
{
return;
}
var currentPage = pagingContext.PageNumber.Value;
var addedEmptyPage = false;
// for up to 4 pages, always render all pages
if (totalNumberPages <= 4)
{
for (var i = 1; i <= totalNumberPages; i++)
{
AddPage(i, pagingContext);
}
return;
}
// for >4 pages, render:
// - first page
// - render the current page or if neighbouring by 1
// - last page
for (var i = 1; i <= totalNumberPages; i++)
{
if (i == 1 ||
i == currentPage || i == currentPage - 1 || i == currentPage + 1 ||
i == totalNumberPages)
{
AddPage(i, pagingContext);
addedEmptyPage = false;
}
else
{
// add ONE empty page only (skip others)
if (addedEmptyPage)
{
continue;
}
this.AddEmptyPage();
addedEmptyPage = true;
}
}
}
private void AddPage(int pageNumber, IPagingContextAspect pagingContext)
{
Pages.Add(new Page(pageNumber, pagingContext.PageNumber.Value == pageNumber,
pagingContext.AsNameValueCollection().SetKey(Constants.SearchContext.Keys.PageNumber, pageNumber).ToQueryString(true)));
}