"System.IndexOutOfRangeException: 在位置 0 处没有任何行"错误！怎么改啊

我的数据库中有数据但总出现dr = ds.Tables["entermx"].Rows[0]；一行有错，不知怎么修改。我是从一个页面的DataGrid中一个链接列实现的一个链接页
public class entergoodsmx : System.Web.UI.Page
    {
        protected System.Web.UI.WebControls.DataGrid DataGrid1;
        public String entergoodsid;
        public DataRow dr;
private void Page_Load(object sender, System.EventArgs e)
        {
            //取得上个页面传递来的参数值
            entergoodsid = Request.Params["entergoodsid"];
            
            SqlConnection sqlcon = new SqlConnection("server=.;uid=sa;pwd=;database=peisong");
            //sqlcon.Open;
            string entermx="select * from entermx where entergoodsid =" + Convert.ToInt32(entergoodsid);
            SqlDataAdapter MyCommandnews = new SqlDataAdapter(entermx,sqlcon);
            DataSet ds = new DataSet ();
            MyCommandnews.Fill(ds,"entermx");
            dr = ds.Tables["entermx"].Rows[0];
}
}