//初始分组
            string resultstr = "select category from dbo.XN_Category";//定义SQL语句
            SqlConnection conn = App_Code.BaseClass.DBCon();//连接DB
            conn.Open();//打开DB
            SqlCommand cmd = new SqlCommand(resultstr, conn);
            SqlDataReader sdr = cmd.ExecuteReader();
            sdr.Read();

            DropDownList1.DataTextField = "category";
            DropDownList1.DataSource = sdr;
            DropDownList1.DataBind();
            conn.Close();