C# 尝试查询正在运行的进程中的模块时出现访问被拒绝异常

我正在尝试获取使用.NET的正在运行进程的列表。我正在使用张贴的问题来做这件事

using (Process p = Process.GetProcessById(pid))
{
     var modules = p.Modules.Cast<ProcessModule>().Where(
                    m => m.ModuleName.StartsWith("mscor", StringComparison.InvariantCultureIgnoreCase));
     if (modules.Any())
         Console.WriteLine(string.Format("{0} used .NET", pid));
}

我做错了什么

Unhandled Exception: System.ComponentModel.Win32Exception: Access is denied
   at System.Diagnostics.ProcessManager.OpenProcess(Int32 processId, Int32 access, Boolean throwIfExited)
   at System.Diagnostics.NtProcessManager.GetModuleInfos(Int32 processId, Boolean firstModuleOnly)
   at System.Diagnostics.ProcessManager.GetModuleInfos(Int32 processId)
   at System.Diagnostics.Process.get_Modules()
   at ConsoleApplication1.Program.Main(String[] args) in c:\Code\ConsoleApplication1\ConsoleApplication1\Program.cs:line