MongoDb 中的PageFilter

PageFilter的定义


 

public abstract class FilterBase    {        public string Prefix { get; set; }        protected abstract void Internal_ApplyFilter<TDefaultDocument>(MongoCursor<TDefaultDocument> cursor);        private readonly IList<FilterBase> _childFilters = new List<FilterBase>();        public T WithFilter<T>(T filter) where T : FilterBase        {            _childFilters.Add(filter);            return filter;        }        public void AddFilter<T>(T filter) where T : FilterBase        {            _childFilters.Add(filter);        }        protected FilterBase(string prefix)        {            Prefix = prefix;        }        protected FilterBase(FilterBase relatedFilter)        {            Prefix = relatedFilter.Prefix;            relatedFilter.AddFilter(this);        }        public MongoCursor<TDefaultDocument> ApplyFilter<TDefaultDocument>(MongoCursor<TDefaultDocument> cursor)        {            Internal_ApplyFilter(cursor);            foreach (var childFilter in _childFilters)            {                childFilter.ApplyFilter<TDefaultDocument>(cursor);            }            return cursor;        }    } public class PagingFilter : FilterBase    {        private int _itemsPerPage = 50;        private int _currentPage = 1;        private int _pagesPerPaginate = 9;        public bool IsHttpPost { get; private set; }        public PagingFilter(FilterBase filterBase, IBaseFilterContext context)            : base(filterBase)        {            IsNeedPaging = true;            UpdateContext(filterBase.Prefix, context);        }        private PagingFilter(string prefix)            : base(prefix)        {            IsNeedPaging = true;        }        public PagingFilter(string prefix, IBaseFilterContext context, int itemsPerPage = 50)            : this(prefix)        {            UpdateContext(prefix, context, itemsPerPage);        }        private void UpdateContext(string prefix, IBaseFilterContext context, int itemsPerPage = 50)        {            ItemsPerPage = itemsPerPage;            if (context == null)            {                throw new ArgumentNullException("context");            }            try            {                var currentPage = Convert.ToInt32(context.Parameter(PrivateCurrentPageParamName(prefix)));                if (currentPage > 0)                {                    _currentPage = currentPage;                }            }            catch (Exception)            {            }            _itemsPerPage = itemsPerPage;            try            {                itemsPerPage = Convert.ToInt32(context.Parameter(PrivateItemsPerPageParamName(prefix)));                if (itemsPerPage > 0)                {                    _itemsPerPage = ItemsPerPage;                }            }            catch (Exception)            {            }        }        public PagingFilter(int pageNumber, int itemsPerPage, string prefix)            : this(prefix)        {            _currentPage = pageNumber;            ItemsPerPage = itemsPerPage;        }        private string PrivateItemsPerPageParamName(string prefix)        {            return string.Format("{0}ip", prefix);        }        public string ItemsPerPageParamName        {            get { return PrivateItemsPerPageParamName(Prefix); }        }        private string PrivateCurrentPageParamName(string prefix)        {            return string.Format("{0}cp", prefix);        }        public string CurrentPageParamName        {            get { return PrivateCurrentPageParamName(Prefix); }        }        public int Skip        {            get            {                return (CurrentPage - 1) * _itemsPerPage;            }        }        public int Take        {            get            {                return _itemsPerPage;            }            set            {                _itemsPerPage = value;            }        }        public bool IsNeedPaging { get; set; }        public long TotalCount { get; set; }        public int CurrentPage        {            get            {                if (_currentPage <= 0)                {                    return 1;                }                return _currentPage;            }        }        public bool IsCurrentPage(long page)        {            return CurrentPage == page;        }        public long PageEnd        {            get            {                var pageEnd = CurrentPage * ItemsPerPage;                if (pageEnd > TotalCount)                {                    return TotalCount;                }                return pageEnd;            }        }        public int ItemsPerPage        {            get            {                return _itemsPerPage;            }            set            {                _itemsPerPage = value;            }        }        public long TotalPagesCount        {            get            {                return TotalCount / ItemsPerPage +                                 ((TotalCount % ItemsPerPage > 0) ? 1 : 0);            }        }        public bool FirstPage        {            get            {                return CurrentPage == 1;            }        }        public bool LastPage        {            get            {                return CurrentPage >= TotalPagesCount;            }        }        public long[] PaginationIndexes        {            get            {                var pageWindow = (_pagesPerPaginate - 1) / 2;                long start = CurrentPage - pageWindow;                if (start < 1)                {                    start = 1;                }                long end = CurrentPage + pageWindow;                if (end < _pagesPerPaginate)                {                    end = _pagesPerPaginate;                }                if (end > TotalPagesCount)                {                    end = TotalPagesCount;                    start = TotalPagesCount - _pagesPerPaginate + 1;                }                if (start < 1)                {                    start = 1;                }                var retVal = new long[end - start + 1];                for (int i = 0; i < retVal.Length; i++)                {                    retVal[i] = start++;                }                return retVal;            }        }        /*public MongoCursor<TDefaultDocument> ApplySort<TDefaultDocument>(MongoCursor<TDefaultDocument> cursor,            SortByBuilder sort)        {            cursor.SetSortOrder(sort);            throw new NotImplementedException();        }*/        protected override void Internal_ApplyFilter<TDefaultDocument>(MongoCursor<TDefaultDocument> cursor)        {            if (IsNeedPaging)            {                cursor.SetSkip(Skip).SetLimit(Take);                TotalCount = cursor.Count();            }        }        public PagingFilter IsHttpPosting(bool isHttpPost)        {            this.IsHttpPost = isHttpPost;            return this;        }        public PagingFilter SetCurrentPage(int page)        {            _currentPage = page;            return this;        }    }

在Mongo查询时：

pageFilter.ApplyFilter("your_mongo_collection".Find(mainQuery))

在Controller中：

var pagingFilter = new PagingFilter("myd", new RequestFilterProperty(Request),20);

在 View 中：
 

@Html.DisplayFor(x => x.Paging)

DisplayTemplate的定义 :

@using Pearls.MVC@model XXX.Backend.Pagination.PagingFilter           @if (Model.TotalPagesCount > 1){    <ul class="pagination pagination-sm">        <li class="@Model.FirstPage.AssignIfTrue("disabled")">            <a data-ishttppost="@Model.IsHttpPost" data-currentpage="@(Model.CurrentPage - 1)" href="@Url.AddParam(Model.CurrentPageParamName, Model.CurrentPage - 1)">«</a>        </li>        @foreach (var page in Model.PaginationIndexes)        {            <li class="@Model.IsCurrentPage(page).AssignIfTrue("active")">                <a data-ishttppost="@Model.IsHttpPost" data-currentpage="@page" href="@Url.AddParam(Model.CurrentPageParamName, page)">@Html.DisplayFor(x => page)</a>            </li>        }        <li class="@Model.LastPage.AssignIfTrue("disabled")">            <a data-ishttppost="@Model.IsHttpPost" data-currentpage="@(Model.CurrentPage + 1)" href="@Url.AddParam(Model.CurrentPageParamName, Model.CurrentPage + 1)">»</a>        </li>    </ul>    }