Asp.net 自定义 分页导航控件

using System;
using System.ComponentModel;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace ZZZ.WebControls
{
[DefaultProperty("Text"), ToolboxData("<{0}:PageNavigate runat=\"server\" />")]
public class PageNavigate : WebControl, IPostBackEventHandler
{
public PageNavigate() { }
[DefaultValue(1)]
public virtual int CurrentPage
{
get
{
object obj = ViewState["CurrentPage"];
return (obj is int) ? (int)obj : 1;
}
set
{
if(value < MinPage || value > MaxPage)
throw new ArgumentOutOfRangeException();
ViewState["CurrentPage"] = value;
}
}
[DefaultValue(1)]
public virtual int MaxPage
{
get
{
object obj = ViewState["MaxPage"];
return (obj is int) ? (int)obj : 1;
}
set
{
if(value < MinPage)
throw new ArgumentOutOfRangeException();
ViewState["MaxPage"] = value;
}
}
[DefaultValue(1)]
public virtual int MinPage
{
get
{
object obj = ViewState["MinPage"];
return (obj is int) ? (int)obj : 1;
}
set
{
if(value > MaxPage)
throw new ArgumentOutOfRangeException();
ViewState["MinPage"] = value;
}
}
[DefaultValue(10)]
public virtual int ShowPagesCount
{
get
{
object obj = ViewState["ShowPagesCount"];
return (obj is int) ? (int)obj : 10;
}
set
{
ViewState["ShowPagesCount"] = value;