高手看看这段代码有什么问题?谢谢!!

高手看看下面这段代码有什么问题?
    string strpics = "";
 OleDbDataAdapter da = new OleDbDataAdapter("select DefaultPic from info order by id desc", conn);
            DataTable dt= new DataTable();
            da.Fill(dt);
         
            for (int i = 0; i < dt.Rows.Count; i++)
            {
                strpics += dt.Tables[0].Rows[i]["DefaultPic"];
             }

运行错误提示:CS0117: “System.Data.DataTable”并不包含“Tables”的定义应该怎么修改呢?谢谢!!