Tuesday, April 23, 2019

Disable Event Firing when Flow updates a SharePoint list item

There’s a lengthy discussion over at https://powerusers.microsoft.com/t5/Flow-Ideas/Disable-Event-Firing-when-Flow-updates-a-SharePoint-list-item/idc-p/271110 to have a Flow trigger on a SharePoint item being modified, and then be able to update that same item in the workflow without causing it to re-trigger, causing a possible infinite loop.

The workaround posted so far is to check on a specific field if you are to update the item or not. This causes Flow to fire twice per item, one for the actual update, and one where it skips the update based on some status logic.

Melissa Hubbard has a post on the workaround solution over at THE INFINITE LOOP: WHAT IT IS AND HOW TO AVOID IT.

It is also possible to use the ValidateUpdateListItem REST API as well, but you need to ensure you get the dates formatted correctly. I could not make it work for Norwegian locale, but once setting the locale to English I got it working. Examine the output of the action after a test run to see if dates had issues or not.

A big thank you to John Liu for pointing this out, as I missed the trick of setting the date when testing this API when researching this post.


As an update to the JSON payload used in John's post, set bNewDocumentUpdate to true, if you don't want to add a new version to the item you are updating (kind of counter-intuitive).

[Original Post]

The underlying issue causing this behavior is that any update to a SharePoint item will trigger an update event for the list. EXCEPT if you use a method called SystemUpdate, which is only available via the JSOM/CSOM/Native SharePoint API’s, and not the REST API.

This quickly becomes very technical, but until the SharePoint Flow connectors support the ability to update using a System Update, this is what we have to deal with. It is certainly possible to overcome this issue, but it involves a bit of XML which might throw you off. If not, read on.

Gotcha in Microsoft Flow when handling SharePoint list item attachments

I’ve written a couple of these, where I in PowerApps allow the user to upload attachments to a list item. This feature can typically be used to upload documents or photos from the end user.

While list attachments work fine they are often easier managed in a separate document library, or perhaps you want to perform some other action on them. And this is where Flow comes into the picture. When the item is saved in SharePoint associate a Flow which triggers on new items in the list.

What is important to note is that when list items with attachments are created, the item is first created, and then each attachment will be a subsequent operation. When this action is performed using a phone or tablet the attachment upload might take some time, and Flow might very well trigger before all the attachments are done uploading - the effect being that Flow will miss some of the attachments, and your business process can miss some important data.