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 already spun off the main gui thread.

foreach (cpsComms.cpsSerial ser in availPorts) {     Thread t = new Thread(new ParameterizedThreadStart(lookForValidDev));     t.Start((object)ser);//start thread and pass it the port } 

I want the next line of code to wait until all the threads have finished. I've tried using a t.join in there, but that just processes them linearly.

Answer 1

List<Thread> threads = new List<Thread>(); foreach (cpsComms.cpsSerial ser in availPorts) {     Thread t = new Thread(new ParameterizedThreadStart(lookForValidDev));     t.Start((object)ser);//start thread and pass it the port     threads.Add(t); } foreach(var thread in threads) {     thread.Join(); } 

Edit

I was looking back at this, and I like the following better

availPorts.Select(ser =>       {           Thread thread = new Thread(lookForValidDev);           thread.Start(ser);           return thread;       }).ToList().ForEach(t => t.Join());