防止石英立即着火.净的事件

当我创建一个简单的触发器并将其分配给调度程序时，它会立即触发，然后在预定的间隔内再次触发。如何使它只在指定的时间开火?

// construct a scheduler factory
ISchedulerFactory schedFact = new StdSchedulerFactory();
// get a scheduler
IScheduler sched = schedFact.GetScheduler();            
// construct job info
JobDetail jobDetail = new JobDetail("myJob", "Default", typeof(DumbJob));
// Example trigger to fire after 1 minute, no repeat
Trigger trigger = TriggerUtils.MakeMinutelyTrigger(1, 0);
// Schedule the job
trigger.Name = "demoTrigger";
sched.ScheduleJob(jobDetail, trigger);                       
sched.Start();  
public class DumbJob : IJob
{
   public DumbJob()
   {
   }
    public void Execute(JobExecutionContext context)
    {
        MessageBox.Show("Dumb job is running");
    }
}

     trigger.StartTimeUtc = TriggerUtils.GetEvenMinuteDate(DateTime.Now.AddMinutes(1));