protected void ButtonDel_Click(object sender, EventArgs e) { if (Request.QueryString["Cid"] != null) { string Cid = Request.QueryString["Cid"]; LearnSite.BLL.Courses coursebll = new LearnSite.BLL.Courses(); coursebll.Delete(Int32.Parse(Cid)); System.Threading.Thread.Sleep(1000); Response.Redirect("~/Teacher/course.aspx", false); } }