//định nghĩa class chia trang thường dùng
public class Pager
{
public Pager(
int totalItems,
int currentPage = 1,
int pageSize = 10,
int maxPages = 10)
{
// calculate total pages
var totalPages = (int)Math.Ceiling((decimal)totalItems / (decimal)pageSize);
// ensure current page isn't out of range
if (currentPage < 1)
{
currentPage = 1;
}
else if (currentPage > totalPages)
{
currentPage = totalPages;
}
int startPage, endPage;
if (totalPages <= maxPages)
{
// total pages less than max so show all pages
startPage = 1;
endPage = totalPages;
}
else
{
// total pages more than max so calculate start and end pages
var maxPagesBeforeCurrentPage = (int)Math.Floor((decimal)maxPages / (decimal)2);
var maxPagesAfterCurrentPage = (int)Math.Ceiling((decimal)maxPages / (decimal)2) - 1;
if (currentPage <= maxPagesBeforeCurrentPage)
{
// current page near the start
startPage = 1;
endPage = maxPages;
}
else if (currentPage + maxPagesAfterCurrentPage >= totalPages)
{
// current page near the end
startPage = totalPages - maxPages + 1;
endPage = totalPages;
}
else
{
// current page somewhere in the middle
startPage = currentPage - maxPagesBeforeCurrentPage;
endPage = currentPage + maxPagesAfterCurrentPage;
}
}
// calculate start and end item indexes
var startIndex = (currentPage - 1) * pageSize;
var endIndex = Math.Min(startIndex + pageSize - 1, totalItems - 1);
// create an array of pages that can be looped over
var pages = Enumerable.Range(startPage, (endPage + 1) - startPage);
// update object instance with all pager properties required by the view
TotalItems = totalItems;
CurrentPage = currentPage;
PageSize = pageSize;
TotalPages = totalPages;
StartPage = startPage;
EndPage = endPage;
StartIndex = startIndex;
EndIndex = endIndex;
Pages = pages;
}
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; }
public int StartIndex { get; private set; }
public int EndIndex { get; private set; }
public IEnumerable<int> Pages { get; private set; }
}
//cách dùng trong mvc razor view
//css boostrap mặc định
if (pager != null && pager.Pages.Any())
{
<nav class="table-responsive">
<ul class="pagination justify-content-center d-flex flex-wrap">
@if (pager.CurrentPage > 1)
{
<li class="page-item">
<a class="page-link" href="@Url.Action("Index", "Home")">Trang đầu</a>
</li>
<li class="page-item">
<a class="page-link" href="@Url.Action("Index", "Home")?p=@(pager.CurrentPage - 1)">Trước</a>
</li>
}
@foreach (var p in pager.Pages)
{
<li class="page-item @(p == pager.CurrentPage ? "active" : "")">
<a class="page-link" href="@Url.Action("Index", "Home")?p=@p">@p</a>
</li>
}
@if (pager.CurrentPage < pager.TotalPages)
{
<li class="page-item">
<a class="page-link" href="@Url.Action("Index", "Home")?p=@(pager.CurrentPage + 1)">Tiếp</a>
</li>
<li class="page-item">
<a class="page-link" href="@Url.Action("Index", "Home")?p=@(pager.TotalPages)">Trang cuối</a>
</li>
}
</ul>
</nav>
}
