TdPeriodTimeWithTimeZone x = TdPeriodTimeWithTimeZone.Null;
TdPeriodTimeWithTimeZone y = new TdPeriodTimeWithTimeZone(
       new TdTimeWithTimeZone(10, 10, 10, 0, new Timespan(8, 0, 0)), 
       new TdTimeWithTimeZone(12, 11, 30, 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 = TdPeriodTimeWithTimeZone.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").
}