Close Serial COM Port safely in C#

See more:

C#

Windows

threads

serial-port

main()
{

thread_B.start();
thread_A.start();

}


public void Thread_A()
{
    while(true)
        if (State == 1)
        {
            try
            {
                Thread_B.Interrupt();
                if (!thr.Join(5000))
                {
                    Thread_B.Abort();
                    GC.Collect();
                    Thread_B.ExecutionContext.Dispose();
                    //    State = 0;
                    // From here i want to end thread safely    
                    // Application must not restart
                   
                }
                Console.WriteLine("\nInsert_Dongle");
            }
            catch (Exception e)
            { }
        }
}


Thread Thread_B= new Thread(delegate()
{
    State = TLoop();
});

public static int TLoop()
{

while(true)
// some error found
return 1;//


}

i am opening serial port in thread _B
if some one removes the serial cable when code is running incoming data stops but the serial port is still opened if i tried to close the serial port it gives

" unhandled exception system.ObjectDisposedException occured in mscorlib.dll addition information : Safe handle has been closed"


how to close the comport?