The System.Diagnostics namespace contains functions that allow you to manage processes, threads, eventlogs and performance information.

The System.Diagnostics.Process object gives you access to functionality enabling you to manage system processes and threads.

Add this line to your using list:

using System.Diagnostics;

You can get a list of ProcessThreads in a process by using the Process.Threads property, which returns a ProcessThreadCollection object.

Here’s a code example for you, assuming that you already have a Process object named theProcess.

ProcessThreadCollection threadlist = theProcess.Threads;

foreach(ProcessThread theThread in threadlist){
   Console.WriteLine("Thread ID:{0} Priority: {1} Started: {2}", 
  theThread.Id, theThread.PriorityLevel, theThread.StartTime);
}