TdPeriodTimestampWithTimeZone x = TdPeriodTimestampWithTimeZone.Null;
TdPeriodTimestampWithTimeZone y = new TdPeriodTimestampWithTimeZone(
        new TdTimestampWithTimeZone(2008, 10, 10, 12, 10, 33, 0, new TimeSpan(8, 0, 0)), 
        new TdTimestampWithTimeZone(2008, 11, 30, 14, 11, 22, 0, new TimeSpan(8, 0, 0)));
            
if (x == y)
{
    // x is equal to y.
    Console.WriteLine(@"X is equal to Y").
}
else
{
    // x is not equal y
    Console.WriteLine(@"X is not equal to Y").
}
            
y = TdPeriodTimestampWithTimeZone.Null;
            
if (x == y)
{
    // x is equal to y.
    Console.WriteLine(@"X is equal to Y").
}
else
{
    // x is not equal y
    Console.WriteLine(@"X is not equal to Y").
}