C# Waiting for multiple threads to finish

Question

I have a windows forms app that I am checking all the serial ports to see if a particular device is connected.

This is how I spin off each thread. The below code is

Answer 1

Use the AutoResetEvent and ManualResetEvent Classes:

private ManualResetEvent manual = new ManualResetEvent(false);
void Main(string[] args)
{
    AutoResetEvent[] autos = new AutoResetEvent[availPorts.Count];

    manual.Set();

    for (int i = 0; i < availPorts.Count - 1; i++)
        {

        AutoResetEvent Auto = new AutoResetEvent(false);
        autos[i] = Auto;

        Thread t = new Thread(() => lookForValidDev(Auto, (object)availPorts[i]));
        t.Start();//start thread and pass it the port  

    }
    WaitHandle.WaitAll(autos);
    manual.Reset();

}


void lookForValidDev(AutoResetEvent auto, object obj)
{
    try
    {
         manual.WaitOne();
         // do something with obj 
    }
    catch (Exception)
    {

    }
    finally
    {
        auto.Set();
    }


}