/// <summary>
/// This function sets the current time-zone parameters. These parameters control translations from Coordinated Universal Time (UTC) to local time
/// </summary>
/// <param name="tzi"></param>
public static void SetTimeZoneInformation(TimeZoneInformation tzi)
{
// Call CE function (implicit conversion occurs to
// byte[]).
if (!NativeMethods.SetTimeZoneInformation(tzi))
{
throw new System.ComponentModel.Win32Exception(Marshal.GetLastWin32Error(), "Cannot Set Time Zone");
}
}
/// <summary>
/// This function gets the time-zone parameters for the active
/// time-zone. These parameters control translations from Coordinated
/// Universal Time (UTC) to local time.
/// </summary>
/// <param name="tzi"></param>
public static TimeZoneState GetTimeZoneInformation(ref TimeZoneInformation tzi)
{
// Call CE function (implicit conversion occurs to
// byte[]).
TimeZoneState stat;
if ((stat = NativeMethods.GetTimeZoneInformation(tzi)) ==
TimeZoneState.Unknown)
{
throw new System.ComponentModel.Win32Exception(Marshal.GetLastWin32Error(), "Cannot Get Time Zone");
}
return(stat);
}
private void InitFromCityDB(int gmtOffset)
{
TimeZoneInformation mTimeZoneInformation = new TimeZoneInformation();
NativeMethods.InitCityDb();
NativeMethods.ClockLoadAllTimeZoneData();
int nZones = NativeMethods.ClockGetNumTimezones();
IntPtr pZone = IntPtr.Zero;
TZData tmpTZ;
for (int i = 0; i < nZones; i++)
{
int tzIndex;
pZone = NativeMethods.ClockGetTimeZoneDataByOffset(i, out tzIndex);
if (pZone != IntPtr.Zero)
{
tmpTZ = new TZData(pZone);
if ((gmtOffset == tmpTZ.GMTOffset) ||
(gmtOffset == ALL_TIMEZONES_LIST))
{
TimeZoneInformation tzi = new TimeZoneInformation();
tzi.Bias = tmpTZ.GMTOffset;
tzi.DaylightBias = tmpTZ.DSTOffset;
tzi.StandardBias = tmpTZ.StdOffset;
// Don't forget to copy the standard name and
// daylight name to the structure.
tzi.DaylightName = tmpTZ.DSTName;
tzi.StandardName = tmpTZ.Name;
// Copy dates of time's transition
tzi.StandardDate = tmpTZ.StdDate;
tzi.DaylightDate = tmpTZ.DSTDate;
// Copy the display name from the registry to
// the class.
tzi.DisplayName = tmpTZ.ShortName;
this.Add(tzi);
}
}
}
NativeMethods.ClockFreeAllTimeZoneData();
NativeMethods.UninitCityDb();
}
private void InitFromRegistry(int gmtOffset)
{
TimeZoneInformation mTimeZoneInformation = new TimeZoneInformation();
RegistryKey baseKey;
baseKey = Registry.LocalMachine.OpenSubKey("Time Zones", false);
if (baseKey != null)
{
// Enumerate all keys under the base timezone key.
//string cls;
string[] subkeynames = baseKey.GetSubKeyNames();
foreach (string thiskeyname in subkeynames)
{
// Open the enumerated key.
RegistryKey tzKey = baseKey.OpenSubKey(thiskeyname, false);
if (tzKey != null)
{
// Get the display name value for the timezone.
string dispName;
// FIX: TimeZoneInformation.DisplayName contains null character (Bug #29)
dispName = tzKey.GetValue("Display").ToString().Trim();
if (dispName != null)
{
// Extract the offset from GMT from the display string.
// The basic format of the string is:
// (GMT-%02d:%02d) <Name>
// The problem is when you are *at* GMT, where the sign
// and the numbers aren't present.
int hoursOffset = 999, minutesOffset = 999;
string hours;
string minutes;
hours = dispName.Substring(4, 3);
minutes = dispName.Substring(8, 2);
// For the case of GMT itself, there is no
// offset in the display name, so we
// set the offset to zero, in that case.
if ((hours[0] == '-') ||
(hours[0] == '+'))
{
hoursOffset = System.Int32.Parse(hours);
minutesOffset = System.Int32.Parse(minutes);
}
else
{
hoursOffset = 0;
minutesOffset = 0;
}
// Compute the timezone's total offset in minutes
int offset = hoursOffset * 60;
if (hoursOffset < 0)
{
offset -= minutesOffset;
}
else
{
offset += minutesOffset;
}
// We now have a value which we can compare to the
// value that the user gave us.
if ((gmtOffset == offset) ||
(gmtOffset == ALL_TIMEZONES_LIST))
{
// Match. Add timezone to list. So far, we have
// the standard time name and the display name.
// We still need to get the DST name and the
// TIME_ZONE_INFORMATION.
string dstName;
dstName = tzKey.GetValue("Dlt").ToString();
// Read the time zone information from the
// registry. Unfortunately, this is something
// that only the Control Panel code actually
// knows about, so, if they change it, we break.
TZREG tzr = new TZREG();
int tzrSize = tzr.ToByteArray().Length;
TimeZoneInformation tzi = new TimeZoneInformation();
byte[] btzr;
btzr = (byte[])tzKey.GetValue("TZI");
tzr = new TZREG(btzr);
tzi.Bias = tzr.Bias;
tzi.StandardBias = tzr.StandardBias;
tzi.DaylightBias = tzr.DaylightBias;
tzi.StandardDate = tzr.StandardDate;
tzi.DaylightDate = tzr.DaylightDate;
// Don't forget to copy the standard name and
// daylight name to the structure.
tzi.DaylightName = dstName;
tzi.StandardName = thiskeyname;
// Copy the display name from the registry to
// the class.
tzi.DisplayName = dispName;
this.Add(tzi);
}
} //endif dispname null
// close the timezone key.
tzKey.Close();
} //endif tzkey null
} //end foreach subkeynames
// Close the key.
baseKey.Close();
}
}
