Add files to queue: before or after thread.Start()

i have windows service process xml files in queue. files in queue added filesystemwatcher event when files created.

the code is:

namespace xmlftp  {      public class xml_processor : servicebase      {          public string s_folder { get; set; }          public xml_processor(string folder)          {              s_folder = folder;          }          thread worker;          filesystemwatcher watcher;          directoryinfo my_folder;          public static autoresetevent resetevent { get; set; }          bool running;            public bool start()          {              my_folder = new directoryinfo(s_folder);                            bool success = true;              running = true;              worker = new thread(new threadstart(serviceloop));              worker.start();                // add files queue filesystemwatcher event              return (success);          }            public bool stop()          {              try              {                  running = false;                  watcher.enableraisingevents = false;                  worker.join(servicesettings.threadjointimeout);              }              catch (exception ex)              {                  return (false);              }              return (true);          }            public void serviceloop()          {              string filename;              while (running)              {                  thread.sleep(2000);                  if (processingqueue.count > 0)                  {                      // process file , write info db.                  }              }          }
        void watcher_created(object sender, filesystemeventargs e)
        {   
           case watcherchangetypes.created:// add files queue
        }

it works perfectly, want add other files queue. these files not triggered filesystemwatcher. there code it.

detectxml(my_folder); // add other files queue

there files processed service serviceloop method. question should place code detectxml(my_folder)?

before worker.start() is

my_folder = new directoryinfo(s_folder);  detectxml(my_folder);        bool success = true;  running = true;  worker = new thread(new threadstart(serviceloop));  worker.start();

or after worker.start(), likely

my_folder = new directoryinfo(s_folder);  bool success = true;  running = true;  worker = new thread(new threadstart(serviceloop));  worker.start();  detectxml(my_folder);

or doesn't matter @ all. thank you.

hi,

a linkedlist<t> isn't thread safe - see thread safety in class documentation - , , applies collections in system.collections.generic namespace.

here can/will result in problems. example initial post:

    while (running)     {         thread.sleep(2000);         if (processingqueue.count > 0)         {             // process file , write info db.         }     }

as access processingqueue.count isn't protected lock, count can change, if different thread alters "queue". result process file part may fail. that's case if implement count property as:

public static int count { 	get { lock (syncroot) return _files.count; } }

as lock released early.

with blockingcollection<t> can replace loop using getconsumingenumerable. foreach block until new element available, using sleep or checking count isn't necessary. manage shutdown see cancellation in managed threads

if using .net 2.0/3.5 there (less powerful) approaches - example producer/consumer queue.

regards, elmar

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