Question

我写了一个小型控制台应用程序，它连接远程站点，下载一些数据并进行处理。因为它是网络操作所以我希望我的应用程序足够智能，以便在没有互联网连接时进入暂停状态。如果互联网连接可用，它应该恢复工作。

到目前为止我所做的是如果我运行应用程序，它开始从远程站点下载数据。如果我断开互联网连接，它会通过显示适当的信息正确运行。但是一旦网络连接启动，它就会恢复，并且只会在while循环的一次迭代中下载数据。

以下是代码：

class Program
{
    static bool networkIsAvailable = false;
    static StreamWriter writer = null;
    static int i = 1;
    static string URI = "http://xxxxxxxxxxxxxxxxxxxxxxxxxxx/" + i + "/";

    static void Main(string[] args)
    {
        writer = new StreamWriter("c:\\StudentsList.txt", true);

        NetworkChange.NetworkAvailabilityChanged += new NetworkAvailabilityChangedEventHandler(NetworkChange_NetworkAvailabilityChanged);
        NetworkInterface[] nics = NetworkInterface.GetAllNetworkInterfaces();
        foreach (NetworkInterface nic in nics)
        {
            if (
                (nic.NetworkInterfaceType != NetworkInterfaceType.Loopback && nic.NetworkInterfaceType != NetworkInterfaceType.Tunnel) &&
                nic.OperationalStatus == OperationalStatus.Up)
            {
                networkIsAvailable = true;
            }
        }

        if (!networkIsAvailable)
            Console.WriteLine("Internet connection not available! We resume as soon as network is available...");
        else
            ConnectToPUServer();
    }

    public static void ConnectToPUServer()
    {
        var client = new WebClient();
        while (i < 500 && networkIsAvailable)
        {
            string html = client.DownloadString(URI);
            //some data processing
            Console.WriteLine(i);
            i++;
            URI = "http://xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/" + i + "/";
        }
    }

    static void NetworkChange_NetworkAvailabilityChanged(object sender, NetworkAvailabilityEventArgs e)
    {
        networkIsAvailable = e.IsAvailable;
        if (!networkIsAvailable)
            Console.WriteLine("Internet connection not available! We resume as soon as network is available...");
        while (!networkIsAvailable)
        { 
            //waiting for internet connection
        }
        ConnectToPUServer();
        Console.WriteLine("Complete.");
        writer.Close();
    }
}

恢复后，为什么while ConnectToPUServer的循环只执行一次??

感谢。

Answer 1

如果每次NIC更改状态时都会触发 NetworkChange_NetworkAvailabilityChanged ，则不需要while循环等待连接

我还移动了 writer.close 和方法的结尾 ConnectToPUServer

public static void ConnectToPUServer()
{
    var client = new WebClient();
    while (i < 500 && networkIsAvailable)
    {
        string html = client.DownloadString(URI);
        //some data processing
        Console.WriteLine(i);
        i++;
        URI = "http://xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/" + i + "/";
    }
    Console.WriteLine("Complete.");
    writer.Close();

}

static void NetworkChange_NetworkAvailabilityChanged(object sender, NetworkAvailabilityEventArgs e)
{
    networkIsAvailable = e.IsAvailable;
    if (!networkIsAvailable)
    {
        Console.WriteLine("Internet connection not available! We resume as soon as network is available...");
    }
    else
    {
        ConnectToPUServer();
    }
}

检测Console App C中的Internet连接/断开连接＃

1 个答案: