PowerShell recursion with delegate functions, iterate all lists in all webs
There are many ways to iterate a collection in PowerShell. I just really like using delegate functions. This approach is not native PowerShell but utilises the .NET Action class as a function parameter. Using a delegate function approach, it is possible to create a recursive loop that can be very easily reused in the future just by providing an alternative Action.
The example code I provide below demonstrates how to create a delegate function in PowerShell, how to write a function that accepts one as a parameter, and provides some ready made samples for iterating SharePoint objects, specifically all webs or all lists. I am using some specific SharePoint objects in these samples, however the fundamental pattern can be used to effectively iterate any recursive structure.
foreachDecendentWeb : perform an action on every web below the provided web foreachListInWeb : perform an action on every list in the provided web foreachListInWebAndAllDecendentWebs : perform an action on every list in the current and all decendent webs
Some notes
The below script references ‘TopOfScript.ps1’, it is specifically related to calling SharePoint CSOM from PowerShell. Read about it here on sharepointnutsandbolts.
Making the call, providing the delegate
The utility scipts, recursive functions accepting delegate parameters
As a developer my professional interests are technical and tend to be SharePoint focused. I've been working with SharePoint since 2009 and hope my posts will give back a little to the community that's supported me over this time. I'm also a keen runner (half-marathon) and passionate Brompton bicycle owner.
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