Array of WaitHandles from process handles

[Mark Xa]

Hi,

I am trying to create an array of WaitHandles that contain process handles returned from Process.GetProcesses. The code compiles but at runtime I get a System.NullReferenceException - "Object reference not set to an instance of an object." at the statement whandles[i].SafeWaitHandle = swh;

The code is as follows:

using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;
using System.Diagnostics;
using System.Threading;
using Microsoft.Win32.SafeHandles;

namespace ConsoleApplication2
{
    class Program
    {
        static void Main(string[] args)
        {
            Process[] processlist = Process.GetProcesses();
            List<Process> closeProcesses = new List<Process>();

            foreach (Process p in processlist)
            {
                if (p.ProcessName == "FApp1" || p.ProcessName == "Fapp2" || p.ProcessName == "FApp3")
                {
                    closeProcesses.Add(p);
                }
            }

            int processesOpen = closeProcesses.Count;
            WaitHandle[] whandles = new WaitHandle[processesOpen];

            for (int i = 0; i < processlist.Length; ++i)
            {
                SafeWaitHandle swh = new SafeWaitHandle(closeProcesses[i].Handle, false);
                whandles[i].SafeWaitHandle = swh;
            }

            WaitHandle.WaitAll(whandles);
            System.Console.WriteLine("All closed!");
        }
    }
}

What's wrong?