与任务管理器相比，CPU使用率百分比不准确

Question

我试图获得与任务管理器相同的CPU使用率百分比结果。 对于内存，我使用了这段代码，看来工作正常：

        ObjectQuery wql = new ObjectQuery("SELECT * FROM Win32_OperatingSystem");
        ManagementObjectSearcher searcher = new ManagementObjectSearcher(wql);
        ManagementObjectCollection results = searcher.Get();

        foreach (ManagementObject result in results)
        {
            double TotalVisibleMemorySize = (Convert.ToDouble(result["TotalVisibleMemorySize"])) / (1024 * 1024);
            Console.WriteLine("Total Visible Memory: {0} GB", (TotalVisibleMemorySize).ToString("0.0"));

            double FreePhysicalMemory = (Convert.ToDouble(result["FreePhysicalMemory"])) / (1024 * 1024);
            Console.WriteLine("Free Physical Memory: {0} GB", (FreePhysicalMemory).ToString("0.0"));

            double FreePhysicalMemoryPercent = (FreePhysicalMemory * 100) / TotalVisibleMemorySize;
            Console.WriteLine("Free Physical Memory: {0} %", (FreePhysicalMemoryPercent).ToString("0.0"));

            double UsedPhysicalMemory = TotalVisibleMemorySize - FreePhysicalMemory;
            Console.WriteLine("Used Physical Memory: {0} GB", (UsedPhysicalMemory).ToString("0.0"));

            double UsedPhysicalMemorypercent = 100 - FreePhysicalMemoryPercent;
            Console.WriteLine("Used Physical Memory: {0} %", (UsedPhysicalMemorypercent).ToString("0.0"));
        }

因此，出于相同的想法，我尝试了CPU。我知道这个问题被问过多次，但是我没有找到正确的解决方案。

我正在使用以下代码（我也尝试过_Total）：

        wql = new ObjectQuery("select * from Win32_PerfFormattedData_PerfOS_Processor");
        searcher = new ManagementObjectSearcher(wql);
        results = searcher.Get();
        foreach (ManagementObject obj in results)
        {
            var usage = obj["PercentProcessorTime"];
            var name = obj["Name"];
            Console.WriteLine(name + " : " + usage);
        }

问题：此代码有什么问题，如何更正它才能起作用？还是有什么问题？

PS：我在m_procTimer_Tick事件中使用了这两个代码段，并将计时器设置为1000。