如果您是普通用户，则只会看到自己的进程.

要查看计算机上的所有进程，代码运行时必须是管理员.

If you are a normal user then you will only see your own processes.

To see all processes on your machine you must be an administrator when the code is running.

(这可能是原因)
该成员不能由部分信任的代码使用.
http://msdn.microsoft.com/en-us/library/1f3ys1f9.aspx [ ^ ]

(This probably could be the reason)
This member cannot be used by partially trusted code.
http://msdn.microsoft.com/en-us/library/1f3ys1f9.aspx[^]