C#杀进程与之之子进程

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Management;
using System.Text;
using System.Threading.Tasks;

namespace ProcessDog.Helper
{
    public static class ProcessHelper
    {
        /// <summary>
        /// Kill a process, and all of its children, grandchildren, etc.
        /// </summary>
        /// <param name="pid">Process ID.</param>
        public static void KillProcessAndChildren(int pid)
        {
            // Cannot close 'system idle process'.
            if (pid == )
            {
                return;
            }
            ManagementObjectSearcher searcher = new ManagementObjectSearcher
                    ("Select * From Win32_Process Where ParentProcessID=" + pid);
            ManagementObjectCollection moc = searcher.Get();
            foreach (ManagementObject mo in moc)
            {
                KillProcessAndChildren(Convert.ToInt32(mo["ProcessID"]));
            }
            try
            {
                Process proc = Process.GetProcessById(pid);
                proc.Kill();
            }
            catch (ArgumentException)
            {
                // Process already exited.
            }
        }

    }
}