.net - Listing of detailed COM port names using VisualStudio 2013 C# -

i want list active com ports detailed names (like in windows device manager). i'm using code , works, slow. can take 45 seconds list of 5 com ports! doing wrong here or there faster way this? know there several postings this, haven't found right answer yet.

    private void updateserialports(richtextbox _txtbox)     {          foreach (string portname in system.io.ports.serialport.getportnames())         {             string query = string.format("select * win32_pnpentity caption '%{0}%'", portname);             managementobjectsearcher searcher = new managementobjectsearcher("root\\cimv2", query);             managementobjectcollection coll = searcher.get();             if (coll.count > 0)             {                 foreach (managementbaseobject collobj in coll)                 {                     managementbaseobject obj = collobj;                     _txtbox.appendtext(portname + " " + obj.getpropertyvalue("caption").tostring() + "\r\n");                 }             }             else             {                 _txtbox.appendtext(new serialport(portname).tostring() + "\r\n");             }         }     }