C# WIFI连接状态检测的几种方法小结

WiFi热点 IP：192.168.1.1
网关 IP：192.168.1.1  （此时相同）

但在复杂网络中可能：
WiFi热点 IP：192.168.1.1
网关 IP：10.0.0.1  （被转发，网关在远端）

WiFi断掉时序：
时间1: WiFi连接 → ping 192.168.1.1 → 成功 → ARP缓存MAC地址
时间2: WiFi断开连接
时间3: ping 192.168.1.1 → 使用缓存的MAC地址 → 看似成功（但实际上没有发出去）

using System.Diagnostics;

/// <summary>
/// 清除ARP缓存并验证WiFi实际连接状态
/// </summary>
public static bool VerifyWiFiConnection(string targetIP)
{
    try
    {
        // 步骤1：清除ARP缓存
        ProcessStartInfo psi = new ProcessStartInfo
        {
            FileName = "cmd.exe",
            Arguments = "/c ipconfig /all /flushdns && arp -d",
            UseShellExecute = false,
            RedirectStandardOutput = true,
            CreateNoWindow = true
        };
        
        using (Process process = Process.Start(psi))
        {
            process.WaitForExit();
        }
        
        Thread.Sleep(500); // 等待ARP缓存清除
        
        // 步骤2：执行ping验证
        ProcessStartInfo pingPsi = new ProcessStartInfo
        {
            FileName = "ping.exe",
            Arguments = $"-n 1 {targetIP}",
            UseShellExecute = false,
            RedirectStandardOutput = true,
            CreateNoWindow = true
        };
        
        using (Process pingProcess = Process.Start(pingPsi))
        {
            string output = pingProcess.StandardOutput.ReadToEnd();
            pingProcess.WaitForExit();
            
            // 检查ping是否成功（Reply from 或 bytes=）
            return output.Contains("Reply from") || output.Contains("bytes=");
        }
    }
    catch (Exception ex)
    {
        Console.WriteLine($"Error: {ex.Message}");
        return false;
    }
}

/// <summary>
/// 检测WiFi是否真正连接（比ping更可靠）
/// </summary>
public static bool IsWiFiConnected()
{
    try
    {
        NetworkInterface[] interfaces = NetworkInterface.GetAllNetworkInterfaces();
        
        foreach (NetworkInterface ni in interfaces)
        {
            // 检查是否为WiFi网卡
            if (ni.NetworkInterfaceType == NetworkInterfaceType.Wireless80211 &&
                ni.OperationalStatus == OperationalStatus.Up)
            {
                // 关键：检查 OperationalStatus
                // Up = 连接正常
                // Down = 连接断开
                
                IPInterfaceProperties ipProps = ni.GetIPProperties();
                
                // 额外检查：是否有有效的IP地址
                bool hasValidIP = ipProps.UnicastAddresses
                    .Any(x => x.Address.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork &&
                              !IPAddress.IsLoopback(x.Address) &&
                              x.Address.ToString() != "0.0.0.0");
                
                if (hasValidIP)
                {
                    Console.WriteLine($"WiFi已连接: {ni.Name}");
                    Console.WriteLine($"状态: {ni.OperationalStatus}");
                    return true;
                }
            }
        }
        
        Console.WriteLine("WiFi未连接");
        return false;
    }
    catch (Exception ex)
    {
        Console.WriteLine($"Error: {ex.Message}");
        return false;
    }
}

using System.Management;

/// <summary>
/// 通过WMI检测WiFi实际连接状态
/// </summary>
public static bool IsWiFiReallyConnected()
{
    try
    {
        // 查询网络适配器状态
        ManagementObjectSearcher searcher = new ManagementObjectSearcher(
            "SELECT * FROM Win32_NetworkAdapterConfiguration WHERE IPEnabled=true"
        );
        
        foreach (ManagementObject mo in searcher.Get())
        {
            string description = mo["Description"]?.ToString() ?? "";
            
            if (description.Contains("Wireless") || description.Contains("WiFi"))
            {
                // 检查IP配置是否有效
                object[] ipAddresses = mo["IPAddress"] as object[];
                object[] subnetMasks = mo["IPSubnet"] as object[];
                object[] gateways = mo["DefaultIPGateway"] as object[];
                
                if (ipAddresses != null && ipAddresses.Length > 0 &&
                    gateways != null && gateways.Length > 0)
                {
                    // 再查询网络适配器的物理状态
                    ManagementObjectSearcher adapterSearcher = new ManagementObjectSearcher(
                        $"SELECT * FROM Win32_NetworkAdapter WHERE NetConnectionID='{mo["Description"]}'"
                    );
                    
                    foreach (ManagementObject adapter in adapterSearcher.Get())
                    {
                        // NetEnabled = true 表示真正连接
                        bool isEnabled = (bool)adapter["NetEnabled"];
                        
                        if (isEnabled)
                        {
                            Console.WriteLine($"WiFi真正已连接 (NetEnabled=true)");
                            return true;
                        }
                    }
                }
            }
        }
        
        Console.WriteLine("WiFi未连接");
        return false;
    }
    catch (Exception ex)
    {
        Console.WriteLine($"Error: {ex.Message}");
        return false;
    }
}

using System.Net.NetworkInformation;
using System.Diagnostics;

/// <summary>
/// 获取当前连接的WiFi SSID（最直接的方式）
/// </summary>
public static string GetConnectedWiFiSSID()
{
    try
    {
        ProcessStartInfo psi = new ProcessStartInfo
        {
            FileName = "netsh",
            Arguments = "wlan show interfaces",
            UseShellExecute = false,
            RedirectStandardOutput = true,
            CreateNoWindow = true
        };
        
        using (Process process = Process.Start(psi))
        {
            string output = process.StandardOutput.ReadToEnd();
            process.WaitForExit();
            
            // 解析输出，查找 "SSID"
            string[] lines = output.Split(new[] { Environment.NewLine }, StringSplitOptions.None);
            foreach (string line in lines)
            {
                if (line.Contains("SSID"))
                {
                    // 提取SSID值
                    string[] parts = line.Split(':');
                    if (parts.Length > 1)
                    {
                        string ssid = parts[1].Trim();
                        if (!string.IsNullOrEmpty(ssid) && ssid != "Not associated")
                        {
                            Console.WriteLine($"当前连接WiFi: {ssid}");
                            return ssid;
                        }
                    }
                }
            }
        }
        
        Console.WriteLine("未连接WiFi");
        return null;
    }
    catch (Exception ex)
    {
        Console.WriteLine($"Error: {ex.Message}");
        return null;
    }
}

// 完整的WiFi连接检测流程
public static bool CheckWiFiConnection()
{
    // 第一步：检查网络接口状态（快速）
    if (!IsWiFiConnected())
        return false;
    
    // 第二步：获取SSID确认（直接）
    string ssid = GetConnectedWiFiSSID();
    if (string.IsNullOrEmpty(ssid))
        return false;
    
    // 第三步：获取网关IP
    string gatewayIP = GetWiFiGatewayIP();
    Console.WriteLine($"连接的WiFi: {ssid}");
    Console.WriteLine($"网关IP: {gatewayIP}");
    
    return true;
}