How to set the specific duration time for schedule task

you might be confused by the dropdown list on the For a durant of selection in the trigger window on the schedule task configuration.

we think that we only allow to select from the drop down list to make our choice.





In my case, I need to configure the schedule task to run on sunday from 12:00 AM unitl 8 PM at night. which is 20 hours in total. none of the item meet my criteria in the drop down.

the trick is to select either 12 hours from the dropdown list, then put a focus o the dropdown list control, then change 12 to 20, now the schedule task will be execute for 20 hours on every Sunday.