Once a thread is created, it is in at least one of the System.Threading.ThreadState states until it terminates. ThreadStateException is thrown by methods that cannot perform the requested operation due to the current state of a thread. For example, trying to restart an aborted thread by calling Thread.Start on a thread that has terminated throws a System.Threading.ThreadStateException.

System.Threading.ThreadStateException uses the HRESULT COR_E_THREADSTATE, which has the value 0x80131520.

For a list of initial property values for an instance of System.Threading.ThreadStateException, see the ThreadStateException.#ctor constructors.

The following example demonstrates an error that causes a System.Threading.ThreadStateException exception to be thrown.

using System;
using System.Threading;
public class ThreadWork {
 public static void DoWork() {
 Console.WriteLine("Working thread..."); 
 }
}

class ThreadStateTest{
 public static void Main() {
 ThreadStart myThreadDelegate = new ThreadStart(ThreadWork.DoWork);
 Thread myThread = new Thread(myThreadDelegate);
 myThread.Start();
 Thread.Sleep(0);
 Console.WriteLine("In main. Attempting to restart myThread.");
 try {
 myThread.Start();
 }
 catch (ThreadStateException e) {
 Console.WriteLine("Caught: {0}", e.Message);
 }
 
 }
}
 

The output is