How can I move a task from a Summary Task to another Summary Task in the same task list?

Question

Hey, I tried to move tasks through the SP UI from one Summary Task to other in the same task list, but I didn't find possibility for it.
Then I spent time to learn the SP Client Object Model and now I can read tasks form the list. I see every task has a "FileRef" and a "FileDirRef" field. If I think right these fields show the relation between list elements for example between
a Task and a Summary Task elements.
I changed these fields' values and I tried to Update the ListItem but I got this error message: "Invalid data has been used to update the list item. The field you are trying to update may be read only."
I really need to move tasks what were created below a wrong Summary Task so please explain a method or pattern how I can do this. (I can create a new Task below to any Summary Task and I can set field values but I hope there is a way to really move tasks (I
mean I should change the right field values somehow.).
I can reach the Task List both on the server and client side so I'm very interested in every solution. PowerShell solution is also good for me.
I'm using SharePoint 2010 SP2.
Thank you for your answer and your time. :)
Csaba Marosi

Answer 1

Hi,
According to your post, my understanding is that you want to move a task from one summary task to another in the same task list.
We can do it like this:
We can create a Gantt View for this task list, then copy your tasks inside a summary task, then navigate back to the other summary and paste, then go back to original and delete.
Here is another way for your reference:
SharePoint vs Powershell – Moving List Items between folders
http://sharepointstruggle.blogspot.in/2010/07/sharepoint-vs-powershell-moving-list.html
Best Regards
Dennis Guo
TechNet Community Support