private void CourseList()
{
LearnSite.BLL.Courses course = new LearnSite.BLL.Courses();
int grade = Int32.Parse(DDLgrade.SelectedValue);
int term = Int32.Parse(Session["term"].ToString());
GVCourse.DataSource = course.GetLimitList(grade, term);
string Hid = Request.Cookies["TeacherCookies"].Values["Hid"].ToString();
if (Session[Hid+"pageindex"] != null)
GVCourse.PageIndex = Int32.Parse(Session[Hid+"pageindex"].ToString());
GVCourse.DataBind();
}