quartz.net - Cron expression to be executed every 45 minutes

Question

I want a cron expression which fires every 45 minutes.

According to the documentation, I have created this 0 0/45 * * * ? expression.

But it is fired in a pattern like 12:00, 12:45, 13:00, 13:45, 14:00.

But what I expect and want is to be fired at 12:00, 12:45, 13:30, 14:15.

What am I missing?

Answer 1

Cron is not meant to solve such problems. It defines the exact date and times, when a trigger must be fired, not intervals. Use a simple schedule instead:

TriggerBuilder.Create()
  .StartAt(startDate)
  .WithSimpleSchedule(
    simpleScheduleBuilder => simpleScheduleBuilder.WithIntervalInMinutes(45))
  .Build();

Edit: It's either a simple schedule as above, or multiple cron triggers (Quartz jobs can have multiple triggers):

0 0/45 12/3 * * ?    # 12:00, 12:45, 15:00, 15:45, ...
0 30 13/3 * * ?      # 13:30, 16:30, ...
0 15 14/3 * * ?      # 14:15, 17:15, ...