It's not possible directly, but with a P/Invoke
Put these inside the class:
[StructLayoutAttribute(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;
}
[DllImport("coredll.dll")]
static extern bool SetLocalTime(ref SYSTEMTIME time);
And the code would be:
DateTime Now = DateTime.Now;
SYSTEMTIME SystemNow;
SystemNow.year = (short)Now.Year;
SystemNow.month = (short)Now.Month;
SystemNow.dayOfWeek = (short)Now.DayOfWeek;
SystemNow.day = (short)Now.Day;
SystemNow.hour = (short)Now.Hour;
SystemNow.minute = (short)Now.Minute;
SystemNow.second = (short)Now.Second;
SystemNow.milliseconds = (short)Now.Millisecond;
SetLocalTime(ref SystemNow);