Monitor child processes of a process

Here is the solution that the asker found:

// using System.Management;
public static class ProcessExtensions
{
    public static IEnumerable<Process> GetChildProcesses(this Process process)
    {
        List<Process> children = new List<Process>();
        ManagementObjectSearcher mos = new ManagementObjectSearcher(String.Format("Select * From Win32_Process Where ParentProcessID={0}", process.Id));

        foreach (ManagementObject mo in mos.Get())
        {
            children.Add(Process.GetProcessById(Convert.ToInt32(mo["ProcessID"])));
        }

        return children;
    }
}

[Updated]

Slightly more modern code:

// using System.Management;
public static class ProcessExtensions
{
    public static IList<Process> GetChildProcesses(this Process process) 
        => new ManagementObjectSearcher(
                $"Select * From Win32_Process Where ParentProcessID={process.Id}")
            .Get()
            .Cast<ManagementObject>()
            .Select(mo =>
                Process.GetProcessById(Convert.ToInt32(mo["ProcessID"])))
            .ToList();
}