如何写自定义类啊?并将类引用在页面上??
为了学习这个的用法我的写法如下

1. 创建DiamondHotSpot类

using System;

using System.Data;

using System.Configuration;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Web.UI.HtmlControls;


namespace HotSpotTest

{

  public class DiamondHotSpot : System.Web.UI.WebControls.HotSpot

  {

  public int CenterX

  {

  get

  {

  object val = ViewState["centerx"];

  if (val == null)

  return 0;

  else

  return (int)val;

  }

  set

  {

  ViewState["centerx"] = value;

  }

  }


  public int CenterY

  {

  get

  {

  object val = ViewState["centery"];

  if (val == null)

  return 0;

  else

  return (int)val;

  }

  set

  {

  ViewState["centery"] = value;

  }

  }


  public int Width

  {

  get

  {

  object val = ViewState["width"];

  if (val == null)

  return 0;

  else

  return (int)val;

  }

  set

  {

  ViewState["width"] = value;

  }

  }


  public int Height

  {

  get

  {

  object val = ViewState["height"];

  if (val == null)

  return 0;

  else

  return (int)val;

  }

  set

  {

  ViewState["height"] = value;

  }

  }


  protected override string MarkupName

  {

  get

  {

  return "poly";

  }

  }


  public override string GetCoordinates()

  {

  return CenterX.ToString() + "," +

  (CenterY - Height / 2).ToString() + "," +

  (CenterX + Width / 2).ToString() + "," +

  CenterY.ToString() + "," +

  CenterX.ToString() + "," +

  (CenterY + Height / 2).ToString() + "," +