How to Kill Thread in C#?

Question

I have a thread that opens a form of type MyMessageAlert. This form is a popup window that is opened when I call it. It has a timer which calls a method CloseWindow() after 30 seconds.

m_messagAlert = new MyMessageAlert(); 
ParameterizedThreadStart thStart = new ParameterizedThreadStart(m_messagAlert.setMessage);
Thread thread = new Thread(thStart);
thread.Start(strMessage); //at this point, the MyMessageAlert form is opened.

I have defined a list of type thread:

public List<Thread> m_listThread;

Each time that I create a thread, I add it to my list:

m_listThread.Add(thread);

When I close the application, I want that the form of type MyMessageAlert that was opened, will be closed immediately (without waiting 30 seconds). Problem is that I can't make it stop!

I tried to kill it by going over the list with a loop using the Abort() function:

foreach (Thread thread in m_listThread)
 {
      if (thread.IsAlive)
           thread.Abort();
 }

But it doesn't help.

Answer 1

Maybe you want to use Background-Threads instead of Foreground-Threads. Your application start with at least one Foreground-Thread (main process thread). If you create new Threads using the Thread-class directly (e. g. new Thread(...)), this will be an foreground thread.

An AppDomain is not unloaded when at least one foreground thread is still running. To avoid this behavior you can create a background thread. Typically you use background threads from the ThreadPool-class, or by setting the IsBackground-Property at the thread object directly.

edit: An short explanation at the MSDN.