如何在C#中进行只进,只读的WMI查询？

Question

一位同事告诉我,如果我的WMI系统信息收集查询只是前向和/或只读,那么它们会更快.那讲得通.但是我该怎么办呢？

Answer 1

您需要使用EnumerationOptions类并将其Rewindable属性设置为false.这是一个例子:

using System;
using System.Management;

namespace WmiTest
{
    class Program
    {
        static void Main()
        {
            EnumerationOptions options = new EnumerationOptions();
            options.Rewindable = false;
            options.ReturnImmediately = true;

            string query = "Select * From Win32_Process";

            ManagementObjectSearcher searcher =
                new ManagementObjectSearcher(@"root\cimv2", query, options);

            ManagementObjectCollection processes = searcher.Get();

            foreach (ManagementObject process in processes)
            {
                Console.WriteLine(process["Name"]);
            }

            // Uncomment any of these
            // and you will get an exception:

            //Console.WriteLine(processes.Count);

            /*
            foreach (ManagementObject process in processes)
            {
                Console.WriteLine(process["Name"]);
            }
            */
        }
    }
}

除非您使用它枚举具有大量实例的类(如Cim_DataFile),否则您将看不到任何性能改进,并且您将仅枚举返回的ManagementObjectCollection一次.您也将无法使用ManagementObjectCollection.Count等.至于只读查询,我不知道如何制作它们.