Precondition to prevent "starting" a work item?
2 answers
you would have to write a server side extension to accomplish this, but it is possible.
Ralph has an extension on his blog that closes the parent when the children workitems are closed
https://rsjazz.wordpress.com/2012/11/27/resolve-parent-if-all-children-are-resolved-participant/
to develop these extensions, see the extensions workshop
https://jazz.net/library/article/1000
Ralph has an extension on his blog that closes the parent when the children workitems are closed
https://rsjazz.wordpress.com/2012/11/27/resolve-parent-if-all-children-are-resolved-participant/
to develop these extensions, see the extensions workshop
https://jazz.net/library/article/1000
There are no built in advisers that would prevent this. It would be possible to create an advisor that triggers on changing the state away from new, follows the link and checks if the work item(s) in the chain before are in progress already.
I don't think it is wise to do this, but that is just my personal opinion. If you over-regulate your processes, this does not make the users like them any better.
Anyway, here is some code for a follow action that has a lot of the code you would need. https://rsjazz.wordpress.com/2012/11/27/resolve-parent-if-all-children-are-resolved-participant/ an advisor looks similar to https://rsjazz.wordpress.com/2014/05/26/only-owner-can-close-workitem-advisor/ except for the interface and the return data, the API's used are typically the same.
I don't think it is wise to do this, but that is just my personal opinion. If you over-regulate your processes, this does not make the users like them any better.
Anyway, here is some code for a follow action that has a lot of the code you would need. https://rsjazz.wordpress.com/2012/11/27/resolve-parent-if-all-children-are-resolved-participant/ an advisor looks similar to https://rsjazz.wordpress.com/2014/05/26/only-owner-can-close-workitem-advisor/ except for the interface and the return data, the API's used are typically the same.