c# - Why background thread not exiting when form closes? -

as understand it, if set _mythread.isbackground = true thread should exit when form closed. unfortunately i'm not finding thread exiting. here code looks like:

private void mainform_load(object sender, eventargs e) {     // <snip>     daemon = new daemon();     // <snip> }  public daemon() {     // start main thread of connection checking , work     _mainthread = new thread(() => mainthread(this));     _mainthread.isbackground = true;     _mainthread.start(); }  /// <summary> /// work main thread does. /// </summary> private void mainthread(daemon daemon) {     while(true)     {         try         {             // things.             thread.sleep(2000);            // sleep bit not hammer.         }         catch (exception e)         {             logger.exception(e);         }     } } 

i thought since thread started form setting isbackground=true force close on form exit.

am missing or misinterpreting something?

according documentation background thread wont prevent process terminating. there no guarantee thread finish "nicely", whatever may mean.