protected void btnDel_Click(object sender, EventArgs e)
        {
            bool Del = false;

            for (int i = 0; i < grData.Rows.Count; i++)
            {
                try
                {
                    HtmlInputCheckBox htmlCheckBox = (HtmlInputCheckBox)grData.Rows[i].FindControl("cbxDel");
                    if (htmlCheckBox.Checked)
                    {
                        SliderManager.Delete(int.Parse(htmlCheckBox.Value));
                        Del = true;
                    }
                }
                catch { }
            }
            BindData();
            if (Del)
            {
                this.lblError.Text = "Đã xóa bài viết.";
            }
            else
            {
                this.lblError.Text = "Không có bài viết nào bị xóa.";
            }
        }
        public ActionResult Sil(int?id)
        {
            if (id == null)
            {
                return(new HttpStatusCodeResult(HttpStatusCode.BadRequest));
            }

            Slider slider = _managerSlider.Find(x => x.ID == id.Value);

            if (slider == null)
            {
                return(new HttpStatusCodeResult(HttpStatusCode.BadRequest));
            }
            if (System.IO.File.Exists(Server.MapPath("~/img/Slider/" + slider.SliderYol)))
            {
                System.IO.File.Delete(Server.MapPath("~/img/Slider/" + slider.SliderYol));
            }
            _managerSlider.Delete(slider);
            return(RedirectToAction("Index"));
        }