DataNavigateUrlFormatString='Modify.aspx?id=<%#Eval("youidcolumn") %>'

------解决方案--------------------
 HyperLinkField hk = new HyperLinkField();
       hk.DataNavigateUrlFields=new string[]{"FM_no"};
       hk.HeaderText = "编辑";
       hk.ControlStyle.Width = new Unit(50);
       hk.Text = "编辑";
       hk.DataNavigateUrlFormatString = "Modify.aspx?id={0}";
       GridView1.Columns.Add(hk);