C#获取北京时间与设置系统时间

public static DateTime GetBeijingTime()
{
DateTime dt;

// 返回国际标准时间
// 只使用 timeServers 的 IP 地址，未使用域名
try
{
string[,] timeServers = new string[14, 2];
int[] searchOrder = { 3, 2, 4, 8, 9, 6, 11, 5, 10, 0, 1, 7, 12 };
timeServers[0, 0] = "time-a.nist.gov";
timeServers[0, 1] = "129.6.15.28";
timeServers[1, 0] = "time-b.nist.gov";
timeServers[1, 1] = "129.6.15.29";
timeServers[2, 0] = "time-a.timefreq.bldrdoc.gov";
timeServers[2, 1] = "132.163.4.101";
timeServers[3, 0] = "time-b.timefreq.bldrdoc.gov";
timeServers[3, 1] = "132.163.4.102";
timeServers[4, 0] = "time-c.timefreq.bldrdoc.gov";
timeServers[4, 1] = "132.163.4.103";
timeServers[5, 0] = "utcnist.colorado.edu";
timeServers[5, 1] = "128.138.140.44";
timeServers[6, 0] = "time.nist.gov";
timeServers[6, 1] = "192.43.244.18";
timeServers[7, 0] = "time-nw.nist.gov";
timeServers[7, 1] = "131.107.1.10";
timeServers[8, 0] = "nist1.symmetricom.com";
timeServers[8, 1] = "69.25.96.13";
timeServers[9, 0] = "nist1-dc.glassey.com";
timeServers[9, 1] = "216.200.93.8";
timeServers[10, 0] = "nist1-ny.glassey.com";
timeServers[10, 1] = "208.184.49.9";
timeServers[11, 0] = "nist1-sj.glassey.com";
timeServers[11, 1] = "207.126.98.204";
timeServers[12, 0] = "nist1.aol-ca.truetime.com";
timeServers[12, 1] = "207.200.81.113";
timeServers[13, 0] = "nist1.aol-va.truetime.com";
timeServers[13, 1] = "64.236.96.53";
int portNum = 13;
byte[] bytes = new byte[1024];
int bytesRead = 0;
System.Net.Sockets.TcpClient client = new System.Net.Sockets.TcpClient();
for (int i = 0; i < 13; i++)
{
string hostName = timeServers[searchOrder[i], 1];
try
{
client.Connect(hostName, portNum);
System.Net.Sockets.NetworkStream ns = client.GetStream();
bytesRead = ns.Read(bytes, 0, bytes.Length);
client.Close();
break;
}
catch (Exception)
{
// ignored
}
}
char[] sp = new char[1];
sp[0] = ' ';
dt = new DateTime();
string str1 = System.Text.Encoding.ASCII.GetString(bytes, 0, bytesRead);

string[] s = str1.Split(sp);
if (s.Length >= 2)
{
dt = DateTime.Parse(s[1] + " " + s[2]); // 得到标准时间
dt = dt.AddHours(8);                    // 得到北京时间
}
else
{
dt = DateTime.Parse("2016-1-1");
}
}
catch (Exception)
{
dt = DateTime.Parse("2016-1-1");
}
return dt;
}

[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;
}

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;
}