分页再平常不过的需求，其实也很简单完全可以写百行以内的代码扩展到HtmlHelper上实现，但是为了扩展性，我稍微(这所以是稍微，是因为本人只稍微了解，还不敢说用得很熟练)用了点面向对象的思想对这个分页控件进行了设计，当然设计之前也参考了一些盆友的作品。吸取了一些思想的精华，下面就讲讲怎么设计以及为什么要这么设计
接口部分：
using System.Collections.Generic;namespace MvcPagerx{ /// <summary> /// 分页接口 /// </summary> public interface IPageAble { /// <summary> /// 一个按钮或者少于一个按钮的时候 /// </summary> /// <returns></returns> IList<PageButton> GetBtnLessThanOnePage(); /// <summary> /// 第一页时 /// </summary> /// <returns></returns> IList<PageButton> GetBtnWhenFrist(); /// <summary> /// 最后一页时 /// </summary> /// <returns></returns> IList<PageButton> GetBtnWhenLast(); /// <summary> /// 默认情况 /// </summary> /// <returns></returns> IList<PageButton> GetBtnWhenDefault(); /// <summary> /// 分页设置 /// </summary> PagerSettings PagerSetting { get; set; } }}
此接口主要标明实现类可以被分页，在需要分页的各种情况给出反馈，有
一个按钮或者少于一个按钮的时候
第一页时
最后一页时
默认情况
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Web.Routing; using System.Web.Mvc; namespace MvcPagerx{ /// <summary> /// 能够根据分页按钮生成HTML接口 /// </summary> public interface IGeneratePagerHtmlAble { /// <summary> /// PagerSetting /// </summary> PagerSettings PagerSetting { get ; set ; } /// <summary> /// Generate /// </summary> /// <param name="pageButtons"></param> /// <returns></returns> MvcHtmlString Generate(IList < PageButton > pageButtons); Func < RequestContext, string , int , string > UrlCallback { set ; } }}
这个接口呢用于标明实现类具有生成HTML代码的功能,在这里我们可以看到，传入的参数是IList<PageButton>,返回的是MvcHtmlString，为什么要传入IList<PageButton>,因为这里给这个接口定位很明确就是只是完成将PageButton这种实体列表转换为相应的HTML代码就可以了。那么谁负责生成IList<PageButton>呢，看看上面的IpageAble接口便知道，那就是实现了IpageAble的类，请看下面
实现类部分：
using System.Collections.Generic; using System.Linq; using System.Text;
using System;
namespace MvcPagerx{ /// <summary> /// 普通的分页类 /// </summary> public class NormalPageProc : IPageAble { #region fields private int _StartPageIndex; private int _EndPageIndex; public PagerSettings PagerSetting { get ; set ; } #endregion #region Private Method private void Init() { _StartPageIndex = PagerSetting.CurrentPageIndex - (PagerSetting.NumericPagerCount / 2 ); if (_StartPageIndex + PagerSetting.NumericPagerCount > PagerSetting.PageCount) _StartPageIndex = PagerSetting.PageCount + 1 - PagerSetting.NumericPagerCount; if (_StartPageIndex < 1 ) _StartPageIndex = 1 ; _EndPageIndex = _StartPageIndex + PagerSetting.NumericPagerCount - 1 ; if (_EndPageIndex > PagerSetting.PageCount) _EndPageIndex = PagerSetting.PageCount; } private void AddFristButton(IList < PageButton > pageBtnList) { PageButton fristitem = new PageButton(PagerSetting.FirstPageText, 1 , PagerSetting.CurrentPageIndex == 1 , PageButtonType.FirstPageButton); pageBtnList.Add(fristitem); } private void AddPrevButton(IList < PageButton > pageBtnList) { var previtem = new PageButton(PagerSetting.PrevPageText, PagerSetting.CurrentPageIndex - 1 , PagerSetting.CurrentPageIndex == 1 , PageButtonType.PrevPageButton); pageBtnList.Add(previtem); } private void AddMoreButtonBefore(IList < PageButton > pageBtnList) { if (_StartPageIndex > 1 && PagerSetting.ShowMorePagerItems) { var index = _StartPageIndex - 1 ; if (index < 1 ) index = 1 ; PageButton item = new PageButton(PagerSetting.MorePageText, index, false , PageButtonType.MorePageButton); pageBtnList.Add(item); } } private void AddNumberButton(IList < PageButton > pageBtnList) { for (var pageIndex = _StartPageIndex; pageIndex <= _EndPageIndex; pageIndex ++ ) { var text = pageIndex.ToString(); if (pageIndex == PagerSetting.CurrentPageIndex && ! string .IsNullOrEmpty(PagerSetting.CurrentPageNumberFormatString)) text = String.Format(PagerSetting.CurrentPageNumberFormatString, text); else if ( ! string .IsNullOrEmpty(PagerSetting.PageNumberFormatString)) text = String.Format(PagerSetting.PageNumberFormatString, text); var item = new PageButton(text, pageIndex, false , PageButtonType.NumericPageButton); pageBtnList.Add(item); } } private void AddMoreButtonAfter(IList < PageButton > pageBtnList) { if (_EndPageIndex < PagerSetting.PageCount) { var index = _StartPageIndex + PagerSetting.NumericPagerCount; if (index > PagerSetting.PageCount) index = PagerSetting.PageCount; var item = new PageButton(PagerSetting.MorePageText, index, false , PageButtonType.MorePageButton); pageBtnList.Add(item); } } private void AddNextButton(IList < PageButton > pageBtnList) { var nextitem = new PageButton(PagerSetting.NextPageText, PagerSetting.CurrentPageIndex + 1 , PagerSetting.CurrentPageIndex >= PagerSetting.PageCount, PageButtonType.NextPageButton); pageBtnList.Add(nextitem); } private void AddLastButton(IList < PageButton > pageBtnList) { var lastitem = new PageButton(PagerSetting.LastPageText, PagerSetting.PageCount, PagerSetting.CurrentPageIndex >= PagerSetting.PageCount, PageButtonType.LastPageButton); pageBtnList.Add(lastitem); } private IList < PageButton > AddButtons() { IList < PageButton > pageBtnList = new List < PageButton > (); AddFristButton(pageBtnList); // <---添加第一页 AddPrevButton(pageBtnList); // <---添加前一页 AddMoreButtonBefore(pageBtnList); // <---添加更多按钮（前置） AddNumberButton(pageBtnList); // <---添加数字分页按钮 AddMoreButtonAfter(pageBtnList); // <---添加更多按钮（后置） AddNextButton(pageBtnList); // <---添加下一页 AddLastButton(pageBtnList); // <---添加最后一页 IEnumerable < PageButton > currentPages = pageBtnList.Where(p => p.PageIndex == PagerSetting.CurrentPageIndex); foreach (PageButton btn in currentPages) btn.Disabled = true ; return pageBtnList; } #endregion /// <summary> /// 一个按钮或者少于一个按钮的时候 /// </summary> /// <returns></returns> public IList < PageButton > GetBtnLessThanOnePage() { return new List < PageButton > () { new PageButton(PagerSetting.FirstPageText, 1 , true ,PageButtonType.FirstPageButton) }; } /// <summary> /// 第一页时 /// </summary> /// <returns></returns> public IList < PageButton > GetBtnWhenFrist() { IList < PageButton > defaultPageButtons = GetBtnWhenDefault(); defaultPageButtons.SingleOrDefault(m => m.ButtonType == PageButtonType.PrevPageButton).Hide = true ; defaultPageButtons.SingleOrDefault(m => m.ButtonType == PageButtonType.FirstPageButton).Hide = true ; return defaultPageButtons; } /// <summary> /// 最后一页时 /// </summary> /// <returns></returns> public IList < PageButton > GetBtnWhenLast() { IList < PageButton > defaultPageButtons = GetBtnWhenDefault(); defaultPageButtons.SingleOrDefault(m => m.ButtonType == PageButtonType.NextPageButton).Hide = true ; defaultPageButtons.SingleOrDefault(m => m.ButtonType == PageButtonType.LastPageButton).Hide = true ; return defaultPageButtons; } /// <summary> /// 默认情况 /// </summary> /// <returns></returns> public IList < PageButton > GetBtnWhenDefault() { Init(); return AddButtons(); } }}
此类就是普通的分页生成器，在此类实现了IpageAble中定义的各种情况下需要生成的PageButton列表，然后返回给IGeneratePagerHtmlAble的实现类
如下的NormalPagerHtmlGeenerate
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Web.Routing; using System.Web.Mvc; namespace MvcPagerx{ /// <summary> /// 普通分页HTML代码生成类 /// </summary> internal class NormalPagerHtmlGenerate : IGeneratePagerHtmlAble { private Func < RequestContext, string , int , string > _GetUrlCallback; /// <summary> /// 分页设置 /// </summary> public PagerSettings PagerSetting { get ; set ; } private string WrapPageButton(PageButton btn) { string result = string .Empty; if (btn.Disabled) return String.Format( " <li><a disabled=\"disabled\">{0}</a></li> " , btn.Text); result = String.Format( " <li><a href='{0}'>{1}</a></li> " , _GetUrlCallback(PagerSetting.HtmlRequestContext, PagerSetting.PageParameterName, btn.PageIndex), btn.Text); return result; } /// <summary> /// 生成HTML代码 /// </summary> /// <param name="pageButtons"> 按钮列表 </param> /// <returns></returns> public MvcHtmlString Generate(IList < PageButton > pageButtons) { TagBuilder tagBuilder = new TagBuilder(PagerSetting.TagName); tagBuilder.GenerateId(PagerSetting.TagID); if ( ! string .IsNullOrEmpty(PagerSetting.ClassName)) tagBuilder.AddCssClass(PagerSetting.ClassName); StringBuilder sb = new StringBuilder(); foreach (PageButton btn in pageButtons) { if ( ! btn.Hide) sb.Append(WrapPageButton(btn)); } tagBuilder.InnerHtml = sb.ToString(); return MvcHtmlString.Create(tagBuilder.ToString(TagRenderMode.Normal)); } public Func < RequestContext, string , int , string > UrlCallback { set { _GetUrlCallback = value; } } }
}
交给此类后便能生成HTML代码到前端展示了，还是相当的简单吧，更多的东西直接看代码吧，这里只是提一下大概思路。