c# - NullReferenceException while handling ErrorDataReceived - killed thread -

i'm trying make c# application acts java application wrapper.

one of functions i'm trying implement redirect console output program, unfortunately, when kill java process, whole program freezes.

here code:

private void button1_click(object sender, eventargs e) {     string start = @"myjavaapp.jar";      var startinfo = new processstartinfo("java", start);      startinfo.redirectstandardinput = startinfo.redirectstandarderror = true;     startinfo.useshellexecute = false;     startinfo.createnowindow = true;     process serverproc = new process();     serverproc.startinfo = startinfo;     serverproc.enableraisingevents = true;     serverproc.errordatareceived += new datareceivedeventhandler(serverproc_errordatareceived);     serverproc.exited += new eventhandler(serverproc_exited);      serverproc.start();     serverproc.beginerrorreadline(); }  private void serverproc_errordatareceived(object sender, datareceivedeventargs e) {     invoke(new action(() =>     {         if (e.data.contains("nastything"))         {             system.windows.forms.messagebox.show("something nasty happened in console ");         }         f2.richtextbox1.appendtext(e.data + "\n");     })); } 

i think there wrong thread managing - maybe don't understand yet. anyway, in debug mode vs2012 returns me nullreferenceexception.

can use check if e.data!=null?

private void serverproc_errordatareceived(object sender, datareceivedeventargs e) {     invoke(new action(() =>     {         if (e.data!=null && e.data.contains("nastything"))         {             system.windows.forms.messagebox.show("something nasty happened in console ");         }         if (e.data!=null) f2.richtextbox1.appendtext(e.data + "\n");     })); } 

or use try-catch.