Start no earlier than constraints on parent tasks getting stripped

[Luke Wright]

Hi,

I am writing an application that integrates with MS Project by reading and
writing project plans in XML format. I am also using automation to convert
MPP format to XML format and vice versa. I am finding that when I merge an
XML format project plan into a template (.mpt) file, start no earlier than
constraints on parent tasks are lost. It only happens when I merge with a
template, not when I create an MPP from scratch.

This can be reproduced simply within Project alone, using the following steps:
1. Create a new project plan
2. Create two tasks, A and B with B a child of A
3. Set a start no earlier than date on task A
4. Save the project plan as XML format
5. Open a template (as far as I can tell, any template)
6. Open the XML project plan
7. Choose Merge when prompted
8. Note that the start no earlier than constraint is gone and the task dates
have shifted

I am using MS Project 2007 w/ Service Pack 1.

Unless I'm missing something, this seems like a bug in MS Project to me. Is
there any way to get around this? I could propogate the constraint to child
tasks perhaps, but I'm hoping for a simpler solution.

Any help is greatly appreciated.

Luke Wright

 

[Jack Dahlgren]

It is generally a bad practice to use constraints on summary tasks so this
behavior does not surprise me. The work around is the generally recommended
practice of linking only non-summary tasks and using constraints sparingly.

If you want a constraint for a group of tasks, create a milestone, set the
constraint on it and link any of the other tasks to it.

-Jack Dahlgren
http:/zo-d.com/blog