SharePoint Designer Workflows 2 – Developing a For Each Loop for Workflows

(For those using SharePoint 2010 please see my other post - Create a For Each Loop for Workflows Using SharePoint Designer 2010 - the technique described below will only work for SharePoint 2007)

 1. Introduction: Many times when designing workflows there is a need to use a “For Each Loop”. As you may know a For Each Loop will continue to process an action against a list of items until all items in the list have been processed. While present in all programming languages whether declared, script or object oriented, the For Each Loop is not present in SharePoint Designer workflows, or the other GUI driven workflow tools I know. This article will help you build a For Each Loop for your SharePoint Designer workflow.

2. Scenario: In our simple scenario we want our workflow to run through each of several items in a list and to update each of the items Boolean “Processed” field from No to Yes (For Each list item update Processed field to Yes).

3. Explanation: Essentially we will have two workflows, one to create and delete a new item in the “Loop” list, and the other to update the Data list. The logic for the first workflow looks like this:
a. Create an item in the Loop list

b. Pause (allowing the Loop list workflow to run)

c. Delete the item created in Loop list

The logic for the second workflow looks like this:

a. Update the first item whose “Processed” field is set to No

4. Overview: To build a For Each Loop we will need two SharePoint Lists, the first list will contain our data, and the second list will control the For Each Loop. For our example we will call the first list “Data” and the second list “Loop”. We will also need two SharePoint workflows, one, to create and delete items in the For Each Loop list, and one to update items in the Data list. To create the lists follow these steps:

a. From the SharePoint site create a custom list, call it “Data”

b. From the Data list add a custom Boolean column, call it “Processed”, set it’s default value to No and add it to the default view

c. From the Data list create several list items

d. From the SharePoint site create a second custom list, call it “Loop”

e. From the Loop list create 1 item

5. To create the workflows for these lists follow these steps:

a. From SharePoint Designer create a workflow that is associated with the Loop list, call it “For Each loop”

b. Set this workflow to start automatically when an item is created

c. Create 1 step for the workflow, call it “For Each Loop”

d. Create a condition – If Created By is not empty – this means the workflow will always run

e. Add an Update List Item activity, configure the activity as shown below:

f. Add a Pause for Duration activity, configure the activity to pause for 1 minute

g. Add a Log to History List activity, configure the log to write “For Each Loop – Ran”

h. The complete workflow configuration should appear as below:

i. From SharePoint Designer create a workflow that is associated with the Data list and call it “Process Data”

j. Set this workflow to start automatically when a item is changed

k. Create 1 step for the workflow, call it “Process Data”

l. Create a condition – If Created By is not empty

m. Create a second condition and Processed not equals No – this means the workflow will not run if the Processed equals no

n. Add a Create List Item activity, create a new item in the Loop list, title the new item “New Loop Item”, and output to variable “idLoopListItem” of the type list ID, the activity should appear as below:

o. Add a Pause for Duration activity, pause for 1 minute

p. Add a Update List Item activity, update the current item in Data and change the value of Processed to No

q. Add a Delete Item activity, and delete the item in the Loop list that has the same id as the idLoopListItem or the item you just created (by deleting the item we will keep this list from growing too large in the future). The configuration should appear as below:

r. Add a Log to History List activity, configure the log to write “Processed – Ran”

s. The complete workflow configuration should appear as below:

6. Test the Workflows: To test the workflow we only need to start the For Each Loop workflow from our item in the Loop list.

7. Error Messages: The last item created in the Loop list will have an error occurred in the workflow metadata field. This is because the last item to start cannot find any items that have not been processed. This error can be ignored; it’s part of the normal processing and will eventually be deleted by the Process Data workflow.

8. Thanks: I want to acknowledge Ricky Spears for his article “Looping through Items in a SharePoint List with SharePoint Designer Workflows”, which provided the technique that I describe in this article.