mvc 分页控件(from All-In-One Code Framework )

　　先上代码吧，看看我们能从代码中学到什么。

　　

代码

namespace  CSASPNETMVCPager.Helper
{
     public   class  Pager < T >
    {
        ///   <summary>
         ///  determine how many records displayed in one page
        ///   </summary>
         public   int  pageSize  =   6 ;
    
       ///   <summary>
       ///  instantiate a pager object
       ///   </summary>
       ///   <param name="collection"> datasource which implement ICollection <T></param>
       ///   <param name="currentPageIndex"> Current page index </param>
       ///   <param name="requestBaseUrl"> Request base url </param>
         public  Pager(ICollection < T >  collection, int  currentPageIndex, string  requestBaseUrl)
        {
             int  count  =  collection.Count;            
             int  remainder  =  count  %  pageSize;
             int  quotient  =  count  /  pageSize;

             this .CurrentPageIndex  =  currentPageIndex;
             this .TotalPages  =  remainder  ==   0   ?  quotient : quotient  +   1 ;
             this .RequestBaseUrl  =  requestBaseUrl;
        }
         ///   <summary>
         ///  instantiate a pager object
         ///   </summary>
         ///   <param name="collection"> datasource which implement ICollection <T></param>
         ///   <param name="currentPageIndex"> Current page index </param>
         ///   <param name="requestBaseUrl"> Request base url </param>
         ///   <param name="imgUrlForUp"> image for previous page </param>
         ///   <param name="imgUrlForDown"> image for next page </param>
         public  Pager(ICollection < T >  collection,  int  currentPageIndex,  string  requestBaseUrl,  string  imgUrlForUp,  string  imgUrlForDown)
        {
             int  count  =  collection.Count;
             int  remainder  =  count  %  pageSize;
             int  quotient  =  count  /  pageSize;

             this .CurrentPageIndex  =  currentPageIndex;
             this .TotalPages  =  remainder  ==   0   ?  quotient : quotient  +   1 ;
             this .RequestBaseUrl  =  requestBaseUrl;
             this .ImageUrlForDown  =  imgUrlForDown;
             this .ImageUrlForUp  =  imgUrlForUp;

        }
         ///   <summary>
         ///  instantiate a pager object
         ///   </summary>
         ///   <param name="collection"> datasource which implement ICollection <T></param>
         ///   <param name="currentPageIndex"> Current page index </param>
         ///   <param name="requestBaseUrl"> Request base url </param>
         ///   <param name="imgUrlForUp"> image for previous page </param>
         ///   <param name="imgUrlForDown"> image for next page </param>
         ///   <param name="pagesSize"> determine the size of page numbers displayed </param>
         public  Pager(IList < T >  collection,  int  currentPageIndex,  string  requestBaseUrl,  string  imgUrlForUp,  string  imgUrlForDown,  int  pagesSize)
        {
             int  count  =  collection.Count;
             int  remainder  =  count  %  pageSize;
             int  quotient  =  count  /  pageSize;

             this .CurrentPageIndex  =  currentPageIndex;
             this .TotalPages  =  remainder  ==   0   ?  quotient : quotient  +   1 ;
             this .RequestBaseUrl  =  requestBaseUrl;
             this .ImageUrlForDown  =  imgUrlForDown;
             this .ImageUrlForUp  =  imgUrlForUp;
             this .PagesSize  =   this .PagesSize  >  pagesSize  ?   this .PagesSize : pagesSize;

        }
    
         ///   <summary>
         ///  current page index
         ///   </summary>
         public   int  CurrentPageIndex {  get ;  private   set ; }
         ///   <summary>
         ///  total pages
         ///   </summary>
         public   int  TotalPages {  get ;  private   set ; }
         ///   <summary>
         ///  base url and id value construct a whole url, eg: http://RequestBaseUrl/id
         ///   </summary>
         public   string  RequestBaseUrl {  get ;  private   set ; }
         ///   <summary>
         ///  image for previous page
         ///   </summary>
         public   string  ImageUrlForUp {  get ;  private   set ; }
         ///   <summary>
         ///  image for next page
         ///   </summary>
         public   string  ImageUrlForDown {  get ;  private   set ; }
        ///   <summary>
         ///  size of page numbers which are displayed
        ///   </summary>
         public   int  PagesSize {  get ;  private   set ; }
    }
     ///   <summary>
     ///  Customize pager engineer
     ///   </summary>
     public   static    class  CustomizePager
    {

         ///   <summary>
         ///  Simply input 'Up' or 'Down' for paging
         ///   </summary>
         ///   <param name="currentPageIndex"> current page index </param>
         ///   <param name="totalPages"> total pages </param>
         ///   <param name="requestBaseUrl"> base url and id value construct a whole url, eg: http://baseURL/id </param>    
         public   static   string  CreatePager( int  currentPageIndex,  int  totalPages,  string  requestBaseUrl)
        {
           
            Validate(currentPageIndex, totalPages);
            StringBuilder sb  =   new  StringBuilder();
             if  (currentPageIndex  >   0 )
            {
                sb.Append( string .Format( " <a href=\ " { 0 }\ " >Up</a> " , requestBaseUrl  +   " / "   +  (currentPageIndex  -   1 ).ToString()));

            }
             if  (currentPageIndex  !=  totalPages  -   1 )
            {
                sb.Append( string .Format( " <a href=\ " { 0 }\ " >Down</a> " , requestBaseUrl  +   " / "   +  (currentPageIndex  +   1 ).ToString()));
            }
             return  sb.ToString();
        }

         ///   <summary>
         ///  Use the passed images for paging 
         ///   </summary>
         ///   <param name="currentPageIndex"> current page index </param>
         ///   <param name="totalPages"> total pages </param>
         ///   <param name="requestBaseUrl"> base url and id value construct a whole url, eg: http://baseURL/id </param>    
         ///   <param name="imageUrlForUp"> image for previous page </param>
         ///   <param name="imageUrlForDown"> image for next page </param>
         ///   <returns></returns>
         public   static   string  CreatePager( int  currentPageIndex,  int  totalPages,  string  requestBaseUrl,  string  imageUrlForUp,  string  imageUrlForDown)
        {
           
            Validate(currentPageIndex, totalPages);
            StringBuilder sb  =   new  StringBuilder();
             if  (currentPageIndex  >   0 )
            {
                sb.Append( string .Format( " <a href=\ " { 0 }\ " ><img src={1} style=\ " boder:0px;border - color: #FFFFFF\ " /></a> " , requestBaseUrl  +   " / "   +  (currentPageIndex  -   1 ).ToString(), imageUrlForUp));

            }

             if  (currentPageIndex  !=  totalPages  -   1 )
            {
                sb.Append( string .Format( " <a href=\ " { 0 }\ " ><img src={1} style=\ " boder:0px;border - color: #FFFFFF\ " /></a> " , requestBaseUrl  +   " / "   +  (currentPageIndex  +   1 ).ToString(), imageUrlForDown));

            }

             return  sb.ToString();
        }
         ///   <summary>
         ///  Use arabic numerals and images for paging
         ///   </summary>
         ///   <param name="currentPageIndex"> current page index </param>
         ///   <param name="totalPages"> total pages </param>
         ///   <param name="requestBaseUrl"> base url and id value construct a whole url, eg: http://baseURL/id </param>
         ///   <param name="pagesSize"> size of page numbers which are displayed  </param>
         ///   <param name="imageUrlForUp"> image for previous page </param>
         ///   <param name="imageUrlForDown"> image for next page </param>
         ///   <returns></returns>
         public   static   string  CreatePager( int  currentPageIndex,  int  totalPages,  string  requestBaseUrl,  int  pagesSize,  string  imageUrlForUp,  string  imageUrlForDown)
        {
           
            StringBuilder sb  =   new  StringBuilder();
            Validate(currentPageIndex, totalPages, pagesSize);
             string  href  =   " javascript:void(0) " ;
             // determine whether there is previous page
             if  (currentPageIndex  /  pagesSize  !=   0 )
            {
                href  =   string .Format(requestBaseUrl  +   " / "   +  ((currentPageIndex  /  pagesSize)  *  pagesSize  -   1 ).ToString());
            }

            sb.Append( string .Format( " <a href=\ " { 0 }\ " ><img src=\ " { 1 }\ "  style=\ " boder:0px;border - color: #FFFFFF\ " /></a> " , href, imageUrlForUp));
            sb.Append( " &nbsp;&nbsp; " );
             // the max size of page numbers which are displayed
             int  pageIndexMaxIncrement  =  (currentPageIndex  /  pagesSize  +   1 )  *  pagesSize  >  totalPages  ?  totalPages  -  pagesSize  *  (currentPageIndex  /  pagesSize) : pagesSize;

             // inital page number
             int  pageIndex  =  pagesSize  *  ( int )(currentPageIndex  /  pagesSize);
             for  ( int  i  =   0 ; i  <  pageIndexMaxIncrement; i ++ )
            {
                 if  (pageIndex  ==  currentPageIndex)
                {
                    sb.Append( string .Format( " <a href='{0}' style='{2}'>{1}</a> " ,  " javascript:void(0) " , (pageIndex  +   1 ).ToString(),  " text-decoration:none; " ));

                }
                 else
                {
                    sb.Append( string .Format( " <a href='{0}'>{1}</a> " , requestBaseUrl  +   " / "   +  pageIndex.ToString(), (pageIndex  +   1 ).ToString()));

                }
                sb.Append( " &nbsp;&nbsp; " );
                pageIndex ++ ;
            }
            href  =   " javascript:void(0) " ;
             // determine whether there is next page
             if  (pageIndex  <  totalPages  -   1 )
            {
                href  =   string .Format(requestBaseUrl  +   " / "   + pageIndex.ToString()); //  ((currentPageIndex / pagesSize + 1) * pagesSize - 1).ToString());
            }
            sb.Append( string .Format( " <a href=\ " { 0 }\ " ><img src=\ " { 1 }\ "  style=\ " boder:0px;border - color: #FFFFFF\ " /></a> " , href, imageUrlForDown));

             return  sb.ToString();
        }
         ///   <summary>
         ///  customize html helper method
         ///   </summary>
         ///   <param name="htmlHelper"> HtmlHelper </param>
         ///   <param name="pager"> Pager </param>
         ///   <returns></returns>
         public   static   string  CreatePager < T > ( this  HtmlHelper htmlHelper, Pager < T >  pager)
        {
             if  ( string .IsNullOrEmpty(pager.ImageUrlForDown.ToString())  ||   string .IsNullOrEmpty(pager.ImageUrlForUp.ToString()))
            {
                 return  CreatePager(pager.CurrentPageIndex, pager.TotalPages, pager.RequestBaseUrl);
            }
             else   if  (pager.PagesSize  <=   1 )
            {
                 return  CreatePager(pager.CurrentPageIndex, pager.TotalPages, pager.RequestBaseUrl, pager.ImageUrlForUp.ToString(), pager.ImageUrlForDown.ToString());
            }
             else
            {
                 return  CreatePager(pager.CurrentPageIndex, pager.TotalPages, pager.RequestBaseUrl, pager.PagesSize, pager.ImageUrlForUp.ToString(), pager.ImageUrlForDown.ToString());

            }
        }
         private   static   void  Validate( int  currentPageIndex,  int  totalPages)
        {
             if  (currentPageIndex  <   0 )
            {
                 throw   new  Exception( " The current page indx must not be less than zero " );
            }
             if  (totalPages  <   1 )
            {
                 throw   new  Exception( " The total pages must not be less than 1 " );
            }
             if  (currentPageIndex  >  totalPages  -   1 )
            {
                 throw   new  Exception( " The current page index can't be greater than total pages " );
            }
        }
         private   static   void  Validate( int  currentPageIndex,  int  totalPages,  int  pagesSize)
        {
            Validate(currentPageIndex, totalPages);
             if  (pagesSize  <   0 )
            {
                 throw   new  Exception( " The page size must be greater thatn zero " );
            }
        }
    }
}

 

　　

代码

public  ActionResult Index( int   ?  id)
        {
             int  pageIndex  =  Convert.ToInt32(id);
           List < Employee >  empList = EmployeeSet.Employees;
            int  pagesSize  =   5 ;
            
           Pager < Employee >  pager  =   new  Pager < Employee > (empList , pageIndex, Url.Content( " ~/Home/Index " ), Url.Content( " ~/images/left.gif " ), Url.Content( " ~/images/right.gif " ), pagesSize);
          
           ViewData[ " pager " ]  = pager;
             return  View(empList.Skip(pager.pageSize  *  pageIndex).Take(pager.pageSize));
        }

 

<%= Html.CreatePager < Employee > (ViewData[ " pager " ]  as  Pager < Employee > ) %>

 

　　上面的三段代码，写出Page控件的定义和应用。Page控件的定义，我认为不是很实用，有点太繁琐。因为每个项目中所有的分页样式应该是统一的，我们可以通过在config中做相应的配置，来达到自己的目的。此示例中有一个缺点就是把前后翻页的图片写在Controller中。这是在做项目的角度来分析的，但是对于一个简单的示例这样我感觉很完美了。读了这个例子之后，对于分页我的思路又开阔一些。

　　理想很遥远，但是每天我们都要坚持为理想做点什么。