2

我需要开发一个从 NTP 服务器获取当前时间的应用程序，但我在 Windows 8 Store App 中找不到任何示例。如果我尝试使用普通的 C# 类，它就不起作用。有谁知道如何解决这个问题？

4

3 回答 3

2

我强烈建议避免从 HTML 页面中解析字符串 - 轻微的视图格式更改会破坏您的应用程序。

根据此答案中提供的示例，这是获取正确对象的DatagramSocket改编：DateTime

DatagramSocket socket = new DatagramSocket();
socket.MessageReceived += socket_MessageReceived;
await socket.ConnectAsync(new HostName("time.windows.com"), "123");

using (DataWriter writer = new DataWriter(socket.OutputStream))
{
    byte[] container = new byte[48];
    container[0] = 0x1B;

    writer.WriteBytes(container);
    await writer.StoreAsync();
}

收到消息后，您可以通过内置阅读器处理传入的字节数组：

void socket_MessageReceived(DatagramSocket sender, DatagramSocketMessageReceivedEventArgs args)
{
    using (DataReader reader = args.GetDataReader())
    {
        byte[] b = new byte[48];

        reader.ReadBytes(b);

        DateTime time = GetNetworkTime(b);
    }
}

GetNetworkTime与我提到的示例几乎相同，缓冲区作为参数之一传递：

public static DateTime GetNetworkTime(byte[] rawData)
{
    //Offset to get to the "Transmit Timestamp" field (time at which the reply 
    //departed the server for the client, in 64-bit timestamp format."
    const byte serverReplyTime = 40;

    //Get the seconds part
    ulong intPart = BitConverter.ToUInt32(rawData, serverReplyTime);

    //Get the seconds fraction
    ulong fractPart = BitConverter.ToUInt32(rawData, serverReplyTime + 4);

    //Convert From big-endian to little-endian
    intPart = SwapEndianness(intPart);
    fractPart = SwapEndianness(fractPart);

    var milliseconds = (intPart * 1000) + ((fractPart * 1000) / 0x100000000L);

    //**UTC** time
    var networkDateTime = (new DateTime(1900, 1, 1)).AddMilliseconds((long)milliseconds);

    return networkDateTime;
}

// stackoverflow.com/a/3294698/162671
static uint SwapEndianness(ulong x)
{
    return (uint)(((x & 0x000000ff) << 24) +
                   ((x & 0x0000ff00) << 8) +
                   ((x & 0x00ff0000) >> 8) +
                   ((x & 0xff000000) >> 24));
}
于 2013-05-05T20:21:08.990 回答
1

我想这就是你想要的。

using System.Net;
using System.Net.Http;
using System.Text.RegularExpressions;
using System.Threading.Tasks;

private async Task<DateTime?> GetNistTime()
{
    DateTime? dateTime = null; 
    HttpClient httpClient = new HttpClient();
    HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Get, new Uri("http://nist.time.gov/timezone.cgi?UTC/s/0"));
    HttpResponseMessage httpResponseMessage = await httpClient.SendAsync(request, HttpCompletionOption.ResponseHeadersRead);
    string text = await httpResponseMessage.Content.ReadAsStringAsync();
    if (httpResponseMessage.StatusCode == HttpStatusCode.OK)
    {
        string html = await httpResponseMessage.Content.ReadAsStringAsync();
        string time = Regex.Match(html, @">\d+:\d+:\d+<").Value; //HH:mm:ss format
        string date = Regex.Match(html, @">\w+,\s\w+\s\d+,\s\d+<").Value; //dddd, MMMM dd, yyyy
        dateTime = DateTime.Parse((date + " " + time).Replace(">", "").Replace("<", ""));
    }
    return dateTime;
}
于 2013-04-10T10:59:44.850 回答
0

您需要一个StreamSocket ，然后自己实现 NTP 协议。如果您有用于经典 Windows 的现有 NTP C# 类，则可以调整代码以改用StreamSocket。

于 2013-04-11T08:16:50.383 回答