c# - How to create a List<class> and verify if list contains item already -

easier if show trying do:

public struct server {    public string servername;    public string sitename; }  list<server> targetserverlist = gettargetserverlist(); 

targetserverlist have following data:

sitename: servername: 1  sitename: servername: 2  sitename: b servername: 3  sitename: c servername: 4 

goal: need create list contain following:

sitename: site servernames: 1,2  sitename: site b servernames: 3  sitename: site c servernames: 4 

so created following class:

private class serverspersite {    string servernames;    string sitename; } 

so need loop , add new item new sitename if sitename not exist yet plus add servername it. if exist, need add servername:

foreach (server server in targetserverlist) {   //??missing code } 

how do that? in javascript simple:

  //separate servers per site   var sites=new object();    $("#servergrid").jqgrid('getgridparam', 'data').foreach(function(row)    {     if(!sites[row.sitename])     {         sites[row.sitename] = new array();     }     sites[row.sitename][sites[row.sitename].length] = row.servername;   } 

thank you!

in case dictionary<string, string> or dictionary<string, ilist<string>> better choice.

public struct server {    public string id;    public string sitename; }    private idictionary<string, ilist<string>> servers;  foreach(var server in gettargetserverlist()){     if(!servers.containskey(server.sitename) {         servers.add(server.sitename, new list<string>());     }     servers[server.sitename].add(server.id); }