关于跨站数据提交与页面异常的处理

之前有朋友问到了这个问题，空闲时间写了这段代码，还望大虾们指正。

页面基类代码

using System;
using System.Collections.Generic;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace test
{
    public class pageBase : Page
    {
        private readonly static string _host = "http://localhost:18447";
        private bool _isallowacross = false;
        /// <summary>
        /// 数据提交方式,如get、post或head
        /// </summary>
        public string HttpMethod
        {
            get {
               return Request.HttpMethod.ToLower();
            }
        }

        /// <summary>
        /// 获取客户上次请求的uri地址
        /// </summary>
        public string UrlReferrer
        {
            get {
                return Request.UrlReferrer == null ? "" : Request.UrlReferrer.ToString();
            }
        }

        /// <summary>
        /// 是否允许站外提交数据
        /// </summary>
        public bool IsAllowAcross
        {
            set { _isallowacross = value; }
            get { return _isallowacross; }
        }

        /// <summary>
        /// 检测跨站数据提交
        /// </summary>
        public void CheckAcross()
        {
            if (!IsAllowAcross)
            {
                if (HttpMethod == "post" && UrlReferrer.IndexOf(_host) == -1)
                {
                    Response.Write("禁止跨站提交数据，请求已终止！");
                    Response.End();
                }
            }
        }

        /// <summary>
        /// 捕获异常信息
        /// </summary>
        /// <param name="e"></param>
        protected override void OnError(EventArgs e)
        {
            base.OnError(e);
            Response.Write(string .Format("发生一个未处理的错误，请<a href=\"{0}\">重试</a>！信息：{1}",UrlReferrer,Server.GetLastError().Message));
            Response.End();
        }

        protected override void OnInit(EventArgs e)
        {
            base.OnInit(e);
            CheckAcross();
        }
    }
}

调用页面代码

public partial class index : pageBase
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            if (HttpMethod == "post")
            {
                this.lit.Text = string.Format("欢迎用户：{0}。", Request.Form["txt"]);
                Response.Write(string.Format("客户上次请求Url：{0}<br/>", Request.UrlReferrer));
            }
        }

        ////默认禁止跨站数据提交，可通过重写基类OnInit事件进行开启
        //protected override void OnInit(EventArgs e)
        //{ 
        //    IsAllowAcross = true;
        //    base.OnInit(e);
        //}
    }