Net 分页功能的实现

首先写一个接口

 

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

然后一个类去实现这个类

 

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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; } }     }

那么最后，我们应该如何去调用这个 PagedList的呢？我们先写一个拓展方法

 

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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);         }     }

然后调用的时候就可以这样使用了

 

 

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

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