Net 分頁功能的實現

首先寫一個接口

 

1 2 3 4 5 6

public interface IPagedList     {         int CurrentPageIndex { get; set; }         int PageSize { get; set; }         int TotalItemCount { get; set; }     }

而後一個類去實現這個類

 

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29

public class PagedList<T> : List<T>,IPagedList     {         public PagedList(IList<T> items, int pageIndex, int pageSize)         {             PageSize = pageSize;             TotalItemCount = items.Count;             CurrentPageIndex = pageIndex;             for (int i = StartRecordIndex - 1; i < EndRecordIndex; i++)             {                 Add(items[i]);             }         }           public PagedList(IEnumerable<T> items, int pageIndex, int pageSize, int totalItemCount)         {             AddRange(items);             TotalItemCount = totalItemCount;             CurrentPageIndex = pageIndex;             PageSize = pageSize;         }           public int ExtraCount { get; set; }         public int CurrentPageIndex { get; set; }         public int PageSize { get; set; }         public int TotalItemCount { get; set; }         public int TotalPageCount { get { return (int)Math.Ceiling(TotalItemCount / (double)PageSize); } }         public int StartRecordIndex { get { return (CurrentPageIndex - 1) * PageSize + 1; } }         public int EndRecordIndex { get { return TotalItemCount > CurrentPageIndex * PageSize ? CurrentPageIndex * PageSize : TotalItemCount; } }     }

那麼最後，咱們應該如何去調用這個 PagedList的呢？咱們先寫一個拓展方法

 

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

public static class PageLinqExtensions     {         public static PagedList<T> ToPagedList<T>             (                 this IQueryable<T> allItems,                 int pageIndex,                 int pageSize             )         {             if (pageIndex < 1)                 pageIndex = 1;             var itemIndex = (pageIndex - 1) * pageSize;             var pageOfItems = allItems.Skip(itemIndex).Take(pageSize).ToList();             var totalItemCount = allItems.Count();             return new PagedList<T>(pageOfItems, pageIndex, pageSize, totalItemCount);         }     }

 

而後調用的時候就能夠這樣使用了

 

 

1 2	IQueryable<User> users ;      users.OrderByDescending(u => u.ID).ToPagedList(request.PageIndex, request.PageSize);

 來自 Net 分頁功能的實現