TimeStamp_Sys100NS 从 Win32_PerfFormattedData_PerfProc_Process wmi 返回 null

Question

我正在尝试使用 wmi 查询返回 TimeStamp 属性并收到对象引用错误。当我查看 quickwatch 时，该属性本身为空。我在网上看到过这样的例子，但无法弄清楚为什么这个属性在给我查询的所有其他内容的同时返回 null。

我使用的是 Windows 7 机器

   public List<string> ReturnProcesses()
    {
        string processname;

        ulong N1 = 0;
        ulong D1 = 0;
        ulong N2 = 0;
        ulong D2 = 0;

        ConnectionOptions options = new ConnectionOptions();

        options.Impersonation = ImpersonationLevel.Impersonate;
        List<string> Processlist = new List<string>();
        ManagementScope scope = new ManagementScope("\\root\\cimv2");
        scope.Connect();
        ObjectQuery query = new ObjectQuery("SELECT IDProcess,Name,PrivateBytes,PercentProcessorTime,TimeStamp_Sys100NS FROM Win32_PerfFormattedData_PerfProc_Process");
        ManagementObjectSearcher searcher = new ManagementObjectSearcher(scope, query);
        ManagementObjectCollection queryCollection = searcher.Get();
        try
        {
            foreach (ManagementObject mo in queryCollection)
            {
                ulong privbytes = (ulong.Parse(mo["PrivateBytes"].ToString()) / 1024);
                processname = mo["IDProcess"].ToString() + " " + mo["Name"].ToString() + " " + mo["PercentProcessorTime"].ToString() + " " + privbytes.ToString();
                N2 = ulong.Parse(mo["PercentProcessorTime"].ToString());
                D2 = ulong.Parse(mo["TimeStamp_Sys100NS"].ToString());
                Processlist.Add(processname);
            }
        }
        catch (Exception ex)
        {
            throw ex;
        }
        return Processlist;
    }

Answer 1

您需要使用Win32__PerfRawData_PerfProc_Process 而不是Win32_PerfFormattedData_PerfProc_Process。