url重写，删除数据后重新绑定gridview地址又变回真实的了

     /// <summary>
    /// URL重写以后保持postback地址
    /// </summary>
    public class PageBase : Page
    {
        //// <summary>
        ///  重写默认的HtmlTextWriter方法，修改form标记中的value属性，使其值为重写的URL而不是真实URL。
        /// </summary>
        /// <param name="writer"></param>
        protected override void Render(HtmlTextWriter writer)
        {

            if (writer is System.Web.UI.Html32TextWriter)
            {
                writer = new FormFixerHtml32TextWriter(writer.InnerWriter);
            }
            else
            {
                writer = new FormFixerHtmlTextWriter(writer.InnerWriter);
            }

            base.Render(writer);

        }
    }

    public class FormFixerHtml32TextWriter : System.Web.UI.Html32TextWriter
    {
        private string _url; // 假的URL

        public FormFixerHtml32TextWriter(TextWriter writer)
            : base(writer)
        {
            _url = HttpContext.Current.Request.RawUrl;
        }

        public override void WriteAttribute(string name, string value, bool encode)
        {
            // 如果当前输出的属性为form标记的action属性，则将其值替换为重写后的虚假URL
            if (_url != null && string.Compare(name, "action", true) == 0)
            {
                value = _url;
            }
            base.WriteAttribute(name, value, encode);
        }
    }

    public class FormFixerHtmlTextWriter : System.Web.UI.HtmlTextWriter
    {
        private string _url;
        public FormFixerHtmlTextWriter(TextWriter writer)
            : base(writer)
        {
            _url = HttpContext.Current.Request.RawUrl;
        }

        public override void WriteAttribute(string name, string value, bool encode)
        {
            if (_url != null && string.Compare(name, "action", true) == 0)
            {
                value = _url;
            }

            base.WriteAttribute(name, value, encode);
        }
    }