【分享】一个Asp.net mvc下的分页控件MvcPagerX

 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。

MvcPagerx.rar