c# - specified argument was out of the range of valid values. parameter name index -

while working on legacy asp.net webforms application stumbled following error: "specified argument out of range of valid values. parameter name index". have tabcontainer gridview filled users fullnames , 2 buttonfield (edit & view). when click on view rowcommand, 5 more tabs generated user information ad. works fine until go user tab , click on user name. how can make page remove new 5 tabs created first user , add 5 new ones new user ? thank you

   <ajax:toolkitscriptmanager id="toolkitscriptmanager1" runat="server"> </ajax:toolkitscriptmanager> <ajax:tabcontainer id="tabcontainer1"  oninit="tabcontainer1_init" runat="server" activetabindex = "0" scrollbars="vertical">     <ajax:tabpanel runat="server" headertext="users" id="tabpanel1">     <contenttemplate>       <asp:gridview id="gridview1" runat="server" autogeneratecolumns="false" width= "850px" height = "650px" onrowcommand = "gridview1_rowcommand" >     <columns>  <asp:boundfield datafield="name" headertext="name"/> <asp:boundfield datafield="samaccountname" headertext="username" /> <asp:boundfield datafield="emailaddress" headertext="emailaddress" /> <asp:buttonfield commandname = "view" imageurl ="~/resources/images/view.gif" buttontype = "image"/> <asp:buttonfield commandname = "edit" imageurl ="~/resources/images/edit.gif" buttontype = "image"/>           </columns>         </asp:gridview>            <triggers> <asp:asyncpostbacktrigger controlid="tabcontainer1" eventname="activetabchanged" />              </triggers>     </contenttemplate>      </ajax:tabpanel>    </ajax:tabcontainer>   protected void page_load(object sender, eventargs e)     { if (!ispostback)         {               mydata();         }             }       public void mydata()     {         t = regex.replace(ldap, @"cn=[^,]*,* *", "", regexoptions.cultureinvariant | regexoptions.ignorecase);          try         {              list<string> allusers = new list<string>();             principalcontext ctx = new principalcontext(contexttype.domain, "idea.com", t);             userprincipal usr = new userprincipal(ctx);               // create principalsearcher object.             principalsearcher ps = new principalsearcher(usr);             principalsearchresult<principal> fr = ps.findall();             gridview1.datasource = fr;              gridview1.databind();         }         catch (exception ex)         {         }     }  protected void gridview1_rowcommand(object sender, gridviewcommandeventargs e)     {          int row = int.parse(e.commandargument.tostring());                 item = gridview1.rows[row].cells[1].text;                 var username = gridview1.rows[row].cells[0].text;                 string firstname = username.remove(username.indexof("."));                 directoryentry de = new directoryentry();                 de.path = "ldap://idea.com";                 directorysearcher objadsearcher = new directorysearcher(de);                 de.authenticationtype = authenticationtypes.secure;                 objadsearcher.searchroot = de;                 objadsearcher.filter = "(samaccountname=" + item + ")";                 searchresult results = objadsearcher.findone();                         if (e.commandname == "view")             { if (results.tostring() != "") {int flags = convert.toint32(results.properties["useraccountcontrol"][0].tostring());  if (convert.toboolean(flags & 0x0002)){response.write("<script> alert ('" + "account disabled more 90 days" + "') </script>");            else                     {windowsidentity wi = new windowsidentity(item);   foreach (identityreference group in wi.groups)               {              try                {      result1.add(group.translate(typeof(ntaccount)).tostring());         result1.sort();                }    catch (exception ex) { }                         }   string tabid;     ajaxcontroltoolkit.tabpanel apptab = new ajaxcontroltoolkit.tabpanel();    apptab.headertext = firstname + " " + "application"; apptab.id = string.format("tab{0}{1}",suffix, "tab1");   ajaxcontroltoolkit.tabpanel sharedtab = new ajaxcontroltoolkit.tabpanel();  sharedtab.headertext = firstname + " " + "sharedcommon"; sharedtab.id = string .format ("tab{0}{1}",suffix ,"tab2" );ajaxcontroltoolkit.tabpanel grouptab = new ajaxcontroltoolkit.tabpanel();grouptab.headertext = firstname + " " + "internet/ras"; grouptab.id = string.format("tab{0}{1}",suffix, "tab3");     ajaxcontroltoolkit.tabpanel idtab = new ajaxcontroltoolkit.tabpanel();idtab.headertext = firstname + " " + "info";   idtab.id = string.format("tab{0}{1}",suffix, "tab4");                 tabcontainer1.tabs.add(grouptab);                         tabcontainer1.tabs.add(apptab);                         tabcontainer1.tabs.add(sharedtab);                         tabcontainer1.tabs.add(idtab);}}}