自定义Web DataGrid 翻页控件

下面就是有关DataGrid的源码，本人在此就不在说废话了，有兴趣的朋友可以Download，一看便知。。。

using System;
using System.ComponentModel;
using System.Collections;
using System.Collections.Specialized;
using System.Text;
using System.Text.RegularExpressions;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace WebControlLib.DataGrid
{
 [DefaultProperty("Text"),
 ToolboxData("<{0}:DatagridPager runat=server></{0}:DatagridPager>")]
 public class DatagridPager : System.Web.UI.WebControls.DataGrid
 {

  //Static constants
  private static readonly Regex RX = new Regex(@"^&page=/d+", RegexOptions.Compiled);
  private const string LINK_FIRST = "<a href=?page={0}>[首页]</a>";
  private const string LINK_FIRST_DISABLE = "[首页]";
  private const string LINK_PREV = "<a href=?page={0}>[上页]</a>";
  private const string LINK_PREV_DISABLE = "[上页]";
  private const string LINK_NEXT = "<a href=?page={0}>[下页]</a>";
  private const string LINK_NEXT_DISABLE = "[下页]";
  private const string LINK_LAST = "<a href=?page={0}>[尾页]</a>";
  private const string LINK_LAST_DISABLE = "[尾页]";
  private const string LINK_PAGES = "  第{0}页/共计{1}页  共{2}笔资料";
  //private const string GO_PAGES = "  <input type=submit name=action value=到><input type=text name=go_pages size=3>页";
  private const string GO_PAGES = "  到:<input type=text name=go_pages size=3 onblur='toPages(this)'>页";
  private const string TO_SCRIPT = @"<script language='javascript'>"+
   " var pageCount=3;"+
   " var to_page=0;"+
   " function toPages(e){"+
   "  if(isInteger(e.value)){"+
   "   to_page=parseInt(e.value)>parseInt(pageCount)?pageCount:e.value;"+   
   "   var path = location.href+'?';"+
   "   path = path.substring(0,path.indexOf('?'));"+
   "   window.location.href=path+'?page='+to_page;document.getElementsByName('go_pages').value=to_page;"+
   "  }"+ 
   "  else"+  
   "   e.value=0;"+    
   " }"+
   " function isInteger(inputVal){"+
   "  inputStr = inputVal.toString();"+
   "  for (var i=0; i< inputStr.length; i++){"+
   "   var oneChar = inputStr.charAt(i);"+
   "   if (oneChar < '0' || oneChar > '9')"+
   "    return false;"+
   "   else"+
   "    return true;"+
   "  }"+
   " }"+
   "</script>";
  private const string ScriptKey="HcTextBoxClientScrptKeyWord";

  private const string KEY_PAGE = "page";
  private const string KEY_GO_PAGE = "go_pages";
  private const string COMMA = "?";
  private const string AMP = "&";

  protected string emptyText;
  protected string htmlHiddenSortExpression;
  //private int pageingStyle = 0; //0:表示内定换页方式，1:表示自定义的方式，就是本类的方式。
  private IList dataSource;
  private int pageSize = 10;
  private int currentPageIndex;
  private int itemCount;
  
  override public object DataSource
  {
   set
   {
    //This try catch block is to avoid issues with the VS.NET designer
    //The designer will try and bind a datasource which does not derive from ILIST
    try
    {
     dataSource = (IList)value;
     ItemCount = dataSource.Count;
    }
    catch
    {
     dataSource = null;
     ItemCount = 0;
    }
   }
  }  

  public override int PageSize
  {
   get { return pageSize; }
   set { pageSize = value; }
  }
  
  new protected  int PageCount
  {
   get { return ((ItemCount - 1) / pageSize)+1; }
  }
  
  virtual protected int ItemCount
  {
   get { return itemCount; }
   set { itemCount = value; }
  }
  
  new virtual public int CurrentPageIndex
  {
   get { return currentPageIndex; }
   set { currentPageIndex = value; }
  }

  public string EmptyText
  {
   set { emptyText = value; }
  }

  public string HiddenSortExpression
  {
   get { return htmlHiddenSortExpression; }
   set { htmlHiddenSortExpression = value; }
  }

  public void SetPage(int index)
  {
   OnPageIndexChanged(new DataGridPageChangedEventArgs(null, index));
  }

  override protected void OnLoad(EventArgs e)
  {
   if (Visible)
   {

    string sorts = Context.Request["sort"];
    htmlHiddenSortExpression = (sorts != string.Empty) ? sorts : string.Empty;

    int iGoPages = 0;
    int pages = 1;
    string go_page = Context.Request[KEY_GO_PAGE];
    string page = Context.Request[KEY_PAGE];
    try
    {
     iGoPages = (go_page != null) ? int.Parse(go_page) : 0;
     pages = (page != null) ? int.Parse(page) : 1;
    }
    catch(Exception)
    {
     return;
    }

    if (iGoPages > 0 && iGoPages <= PageCount)
    {
     SetPage(iGoPages - 1);
    }
    else
    {
     SetPage(pages - 1);
    }
   }
  }

  /// <summary>
  /// 将此控件呈现给指定的输出参数。
  /// </summary>
  /// <param name="output"> 要写出到的 HTML 编写器 </param>
  
  protected override void OnPreRender(System.EventArgs e)
  {
   Page.RegisterStartupScript(ScriptKey,TO_SCRIPT);
  }

  /// <summary>
  /// Overriden method to control how the page is rendered
  /// </summary>
  /// <param name="writer"></param>
  override protected void Render(HtmlTextWriter writer)
  {
   
   // Check there is some data attached
   if (ItemCount == 0)
   {
    writer.Write(emptyText);
    return;
   }

   if (AllowPaging == false || PagerStyle.Visible == true)
   {
    base.Render(writer);
    return;
   }

   //Mask the query
   string query = Context.Request.Url.Query.Replace(COMMA, AMP);
   query = RX.Replace(query, string.Empty);

   
   if (htmlHiddenSortExpression != string.Empty)
   {
    if (query.IndexOf("&sort=") >= 0)
    {
     query = query.Substring(0, query.IndexOf("&sort="));
    }
    query = query + "&sort=" + htmlHiddenSortExpression;
   }

   // Call the inherited method
   base.Render(writer);

   //Determin whether next and previous buttons are required
   //Previous button?
   int currentPage = CurrentPageIndex + 1;
   if (currentPage < 1)
   {
    currentPage = 1;
   }

   if (currentPage == 1)
   {
    writer.Write(LINK_FIRST_DISABLE);
    writer.Write(LINK_PREV_DISABLE);
    
    if (PageCount > 1)
    {
     writer.Write(string.Format(LINK_NEXT, (currentPage + 1) + query));
     writer.Write(string.Format(LINK_LAST, (PageCount) + query));
    }
    else
    {
     writer.Write(LINK_NEXT_DISABLE);
     writer.Write(LINK_LAST_DISABLE);
    }
   }
   else
   {
    writer.Write(string.Format(LINK_FIRST, (1) + query));
    writer.Write(string.Format(LINK_PREV, (currentPage - 1) + query));

    if (currentPage == PageCount)
    {
     writer.Write(LINK_NEXT_DISABLE);
     writer.Write(LINK_LAST_DISABLE);
    }
    else
    {
     writer.Write(string.Format(LINK_NEXT, (currentPage + 1) + query));
     writer.Write(string.Format(LINK_LAST, (PageCount) + query));
    }
   }

   writer.Write(string.Format(LINK_PAGES, currentPage, PageCount,ItemCount));
   writer.Write(string.Format(GO_PAGES));
  }

  override protected void OnDataBinding(EventArgs e)
  {
  
   //Work out which items we want to render to the page
   int start = CurrentPageIndex * pageSize;
   int size = Math.Min(pageSize, ItemCount - start);
   
   IList page = new ArrayList();
  
   //Add the relevant items from the datasource
   for (int i = 0; i < size; i++)
    page.Add(dataSource[start + i]);
     
   //set the base objects datasource
   base.DataSource = page;   
   base.OnDataBinding(e);
     
  }

  new public event DataGridPageChangedEventHandler PageIndexChanged;
  
  new virtual protected void OnPageIndexChanged(DataGridPageChangedEventArgs e)
  {  
   if (PageIndexChanged != null)
    PageIndexChanged(this, e);
  }

  //  protected override void AddAttributesToRender(HtmlTextWriter output)
  //  {
  //   output.AddAttribute("onfocus","setday(this);");
  //   base.AddAttributesToRender(output);
  //  }
 }
}