چگونگی بدست آوردن تاریخ دقیق از طریق اینترنت در c#

using System.Net;
using System.Net.Cache;
using System.IO;
using System.Text.RegularExpressions;

 public static DateTime GetNistTime()
{
DateTime dateTime = DateTime.MinValue;

HttpWebRequest request = (HttpWebRequest)WebRequest.Create("http://nist.time.gov/actualtime.cgi?lzbc=siqm9b");
request.Method = "GET";
request.Accept = "text/html, application/xhtml+xml, */*";
request.UserAgent = "Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.1; Trident/6.0)";
request.ContentType = "application/x-www-form-urlencoded";
request.CachePolicy = new RequestCachePolicy(RequestCacheLevel.NoCacheNoStor e); //No caching
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
if (response.StatusCode == HttpStatusCode.OK)
{
StreamReader stream = new StreamReader(response.GetResponseStream());
string html = stream.ReadToEnd();//<timestamp time=\"1395772696469995\" delay=\"1395772696469995\"/>
string time = Regex.Match(html, @"(?<=\btime="")[^""]*").Value;
double milliseconds = Convert.ToInt64(time) / 1000.0;
dateTime = new DateTime(1970, 1, 1).AddMilliseconds(milliseconds).ToLocalTime();
}

return dateTime;
}

• اطلاعات بیشتر

البته شما میتونید توسط تابع Time و Date زمان و تاریخ سیستم خودتونو دریافت کنید مثلاً یک lable داشته باشید و روی این lable توسط کد زیر از سیستم دریافت و نشون بدید

label1.Text = System.DateTime.Now.ToString()

ویا نمونه کد زیر:

using System;

public class Program
{
    public static void Main()
    {
        DateTime myDate = DateTime.Now;

        Console.WriteLine("Year: " + myDate.Year);
        Console.WriteLine("Month: " + myDate.Month);
        Console.WriteLine("Day: " + myDate.Day);
        Console.WriteLine("Today is {0}.", myDate.DayOfWeek.ToString());

        //Assign newDate with the current date added by 3 days
        DateTime newDate = myDate.AddDays(3);
        Console.WriteLine("The date 3 days from now is {0}.", 
                  newDate.ToShortDateString());

        //Assign newdate with the current date subtracted by 3 days
        newDate = myDate.AddDays(-3);
        Console.WriteLine("The date 3 days ago is {0}.", newDate.ToShortDateString()); 
    }
}

که خروجی آن به صورت زیر است:

Year: 2010

Month: 10

Day: 3

Today is Sunday.

The date 3 days from now is 1062010.

The date 3 days ago is 9302010.