Iteration
The Iteration feature is similar to a ForEach loop construct allowing the activity to iterate over a collection of values and take action on or utilise each of those elements in the collection one at a time in the group of value expressions defined for the activity.
The instance value can be referenced in the group of value expressions defined for the activity using the [//Value/...] lookups.
To break out of the iteration loop when continuing the iteration till end is not required or not desirable, set the special variable $__BREAK_ITERATION__ to true (or 1).
Prior to build v2.16.0710.0, during each iteration only the expressions using [//Value/...] lookups were re-evaluated for updated values. As of build v2.16.0710.0, the expressions using [//WorkflowData/..] lookups are also re-evaluated for updated values in each iteration. This implementation now allows a WorkflowData value stored in a one iteration to be accessible for further evaluation and manipulation in the next iteration. e.g. using this enhancement, it is now possible to "traversing a reference hierarchy" to reach a level meeting a specified criteria and then terminate the iteration in these activities using Iteration capability.
As of build v2.17.0721.0, Query definitions can contain [//Value] lookups i.e. the current iteration value can be used to define a Query. However this support is currently only enabled for Send Email Notification activity. This support will be expanded to remaining activities in future releases.
- Create Resource
- Delete Resources
- Update Resources
- Send Email Notification (as of build v2.17.0721.0)
While the Iteration feature is conceptually similar to a ForEach loop, it is not expected to be used to loop over more than a handful of times even though there is no hard-coded upper limit on the maximum number of iterations.
As of build v2.16.0130.0, WAL supports defining a collection of queries in the Query Resources configuration of the supporting activities. Depending on the use case, it may be elegant and more performant to use a query collection than the iteration feature.
Using an Update Resources activity for the Iteration Collection, specify [//Delta/ExplicitMember/Added] to get the resources which are being added in the current request.
Then for each [//Value] in the collection, determine if it is a User and not a Group or other resource type. If it is a User, then added it to the WorkflowData value to be used by other child activities.
| Activity Display Name | Get Users being added to the Group | |
| Iteration | [//Delta/ExplicitMember/Added] | |
| Value Expression | Target | Allow Null |
| IIF(Eq([//Value/ObjectType], "Person"),InsertValues([//Value]),Null()) | [//WorkflowData/UsersAdded] | |
See the TechNet wiki titled MIM2016 MIMWAL: Create workflow for changing e-mail address by Daniel Malmgren on managing ProxyAddresses attribute when the email address of the user changes.