multithreading - c# Background thread gets an error when run in UserControl -

right in usercontrol, have button click event starts thread. i've since moved on using abort(), , trying convert thread background process shut down when close parent form. code is:

public thread t; private void btninitiate_click(object sender, eventargs e)     {         udplistener mylistiner = new udplistener(this);         t.isbackground = true;         t = new thread(() => mylistiner.spreadvalue(mycurrentport, firstticker, secondticker, mybeta));         t.start();     } 

but when run application, error t.isbackground=true says "object reference not set instance of object". i'm wondering going wrong in case.

you need change row order in code:

... t = new thread(() => mylistiner.spreadvalue(mycurrentport, firstticker, secondticker, mybeta)); t.isbackground = true; ... 

because need instantiate thread , use it.