C# 讀取網路上下行（不要使用性能計數器的方式）

C# 讀取網路上下行有多種方式，其中有一種是使用System.Net.NetworkInformation命名空間中的NetworkInterface類和PerformanceCounter類，該方式其實讀的是windows系統的性能計數器中的Network Interface類別的數據。

方式如下：

NetworkInterface networkInterface = NetworkInterface.GetAllNetworkInterfaces()
            .FirstOrDefault(i => i.Name.Equals(interfaceName, StringComparison.OrdinalIgnoreCase));

        if (networkInterface == null)
        {
            Console.WriteLine("Network interface not found.");
            return;
        }

        PerformanceCounter downloadCounter = new PerformanceCounter("Network Interface", "Bytes Received/sec", networkInterface.Description);
        PerformanceCounter uploadCounter = new PerformanceCounter("Network Interface", "Bytes Sent/sec", networkInterface.Description);

        while (true)
        {
            float downloadSpeed = downloadCounter.NextValue();
            float uploadSpeed = uploadCounter.NextValue();

            Console.WriteLine($"Download Speed: {downloadSpeed} bytes/sec");
            Console.WriteLine($"Upload Speed: {uploadSpeed} bytes/sec");

            Thread.Sleep(1000); // 每秒更新一次網速
        }

但是使用性能計數器有時候會拋異常：

異常: System.InvalidOperationException: 類別不存在。
   在 System.Diagnostics.PerformanceCounterLib.CounterExists(String machine, String category, String counter)
   在 System.Diagnostics.PerformanceCounter.InitializeImpl()
   在 System.Diagnostics.PerformanceCounter..ctor(String categoryName, String counterName, String instanceName, Boolean readOnly)
   在 System.Diagnostics.PerformanceCounter..ctor(String categoryName, String counterName, String instanceName)

打開“性能監視器”，點擊“性能”，報錯

 使用網上的各種處理都沒辦法恢復，所以建議使用其它方式獲取網路上下行。

下麵是使用WMI (Windows Management Instrumentation)的方式（需要使用管理員身份運行）：

 string interfaceName = "Ethernet"; // 指定網路介面的名稱

        ManagementObjectSearcher searcher = new ManagementObjectSearcher("SELECT * FROM Win32_PerfFormattedData_Tcpip_NetworkInterface");
        ManagementObjectCollection objects = searcher.Get();

        foreach (ManagementObject obj in objects)
        {
            string name = obj["Name"].ToString();

            if (name.Equals(interfaceName, StringComparison.OrdinalIgnoreCase))
            {
                ulong bytesReceived = Convert.ToUInt64(obj["BytesReceivedPerSec"]);
                ulong bytesSent = Convert.ToUInt64(obj["BytesSentPerSec"]);

                Console.WriteLine($"Download Speed: {bytesReceived} bytes/sec");
                Console.WriteLine($"Upload Speed: {bytesSent} bytes/sec");

                break;
            }
        }

 如果再不行可能是網卡出異常了