using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 
using System.IO; 
using System.Net; 
using System.Net.Sockets; 
using System.Text.RegularExpressions; 
using System.Runtime.InteropServices;
using System.Runtime; 
 /// <summary> 
 /// 网络时间 
 /// </summary> 
 public class NetTime
 {
  /// <summary> 
  /// 获取标准北京时间，读取http://www.beijing-time.org/time.asp 
  /// </summary> 
  /// <returns>返回网络时间</returns> 
  public DateTime GetBeijingTime()
  {
   DateTime dt;
   WebRequest wrt = null;
   WebResponse wrp = null;
   try
   {
    wrt = WebRequest.Create("http://www.beijing-time.org/time.asp");
    wrp = wrt.GetResponse();
    string html = string.Empty;
    using (Stream stream = wrp.GetResponseStream())
    {
     using (StreamReader sr = new StreamReader(stream,Encoding.UTF8))
     {
      html = sr.ReadToEnd();
     }
    }
    string[] tempArray = html.Split(';');
    for (int i = 0; i < tempArray.Length; i++)
    {
     tempArray[i] = tempArray[i].Replace("\r\n", "");
    }
    string year = tempArray[1].Split('=')[1];
    string month = tempArray[2].Split('=')[1];
    string day = tempArray[3].Split('=')[1];
    string hour = tempArray[5].Split('=')[1];
    string minite = tempArray[6].Split('=')[1];
    string second = tempArray[7].Split('=')[1];
    dt = DateTime.Parse(year + "-" + month + "-" + day + " " + hour + ":" + minite + ":" + second);
   }
   catch (WebException)
   {
    return DateTime.Parse("2011-1-1");
   }
   catch (Exception)
   {
    return DateTime.Parse("2011-1-1");
   }
   finally
   {
    if (wrp != null)
     wrp.Close();
    if (wrt != null)
     wrt.Abort();
   }
   return dt;
  }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Net;
using System.Net.Sockets;
using System.Text.RegularExpressions;
using System.Runtime.InteropServices;
using System.Runtime; 
 /// <summary>
 /// 更新系统时间
 /// </summary>
 public class UpdateTime
 {
  //设置系统时间的API函数
  [DllImport("kernel32.dll")]
  private static extern bool SetLocalTime(ref SYSTEMTIME time);
  [StructLayout(LayoutKind.Sequential)]
  private struct SYSTEMTIME
  {
   public short year;
   public short month;
   public short dayOfWeek;
   public short day;
   public short hour;
   public short minute;
   public short second;
   public short milliseconds;
  }
  /// <summary>
  /// 设置系统时间
  /// </summary>
  /// <param name="dt">需要设置的时间</param>
  /// <returns>返回系统时间设置状态，true为成功，false为失败</returns>
  public static bool SetDate(DateTime dt)
  {
   SYSTEMTIME st;
   st.year = (short)dt.Year;
   st.month = (short)dt.Month;
   st.dayOfWeek = (short)dt.DayOfWeek;
   st.day = (short)dt.Day;
   st.hour = (short)dt.Hour;
   st.minute = (short)dt.Minute;
   st.second = (short)dt.Second;
   st.milliseconds = (short)dt.Millisecond;
   bool rt = SetLocalTime(ref st);
   return rt;
  }
}