public static Page <T> GetPage <T>(this Microsoft.EntityFrameworkCore.DbSet <T> list, int page_index, int page_size, Func <T, object> order_by_selector) where T : class
{
//the given index and size are used to select the correct data
//note the OrderBy which is necessary to ensure the selection in the
//correct order
var res = list.OrderBy(order_by_selector)
.Skip(page_index * page_size)
.Take(page_size)
.ToArray();
//in case the query fails or the page size is zero a NotFOund is returned
if (res == null || res.Length == 0)
{
return(null);
}
//we calculate once the total amonut of items of the unput list
var tot_items = list.Count();
//we calculate the total amount of pages. incase the page size is greater than
//the total amount of items we set the total pages to 1
var tot_pages = tot_items / page_size;
if (tot_items < page_size)
{
tot_pages = 1;
}
//we group all the date and return then to the caller
return(new Page <T>()
{
Index = page_index, Items = res, TotalPages = tot_pages
});
}
public static Page <T> GetPages <T>(this Microsoft.EntityFrameworkCore.DbSet <T> list, int index_page, int page_size, Func <T, object> order_by_selector) where T : class
{
var result = list.OrderBy(order_by_selector)
//index = 1; page_size = 3 , skip pages = 3*1 =3
.Skip(index_page * page_size)
.Take(page_size)
.ToArray();
var total_items = list.Count();
var total_pages = total_items / page_size;
return(new Page <T> {
index = index_page,
Items = result,
TotalPages = total_pages
});
}
