How to: For Each Event

Over the last couple of weeks people have asked me how to use the for each loop event in K2. So I thought i would put this quick demo together.

The demo, that i am going to do is going to loop through a list of subscribers and update their status from ‘Not Sent’ to ‘Sent’.

Getting Started

I have created a simple Smart box  SmartObject for demo purposes that has the following properties

  1. 1. Name of type string
  2. Email of type string
  3. Id of type Auto number and Key
  4. Status of type string


I have inserted 3 rows of data with the status of ‘Not Sent’. We will use this SmartObject to use the ‘For Each’ event to loop through the data.

Creating the workflow


Adding the ‘For Each’ event

  1. Open K2 Studio or K2 for Visual Studio ( I am going to use K2 Studio)
  2.  Create a new workflow solution called ‘For Each Demo’
  3. Rename the workflow from process 1 to ‘ForEachWorkflow’
  4. Once the workflow canvas has loaded up
  5. Drag the ‘for each’ event on to the canvas
  6. In the event wizard, give the event the name ‘Loop demo’
  7. Click on Source ico icon, so the drop down list disappears  and open the context browser
  8. In the 1st tab (Environment) , expand ‘SmartObject Services’
  9. Go to the SmartObject you want to use and expand the list method you want to use
  10. Drag the property that you want to use, normally the primary key into the event box
  11. The SmartObject wizard loads up, click ‘Next’ and ‘Next’ again
  12. In ‘Select a return property’ make sure the ‘id’ value is selected.
  13. Click ‘Next’, make sure ‘Return all Results that match filter’ is selected.
  14. Click ‘Finish’
  15. For the reference name, enter in the name ‘Dummy Data Reference’
  16. For the index name, enter in the name ‘Dummy Index’
  17. Click on ‘Finish’

This slideshow requires JavaScript.

Interacting with the for each item

  1. Back in the canvas, you will notice there are now two line rules coming out of the activity
  2. Drag the placeholder event on the canvas and name both the event and activity with the name ‘End’
  3. Drag the ‘line’ named ‘No more items’ to the end activity
  4. Create a new activity on the canvas and name it ‘Status Change’
  5. Drag the SmartObject Event into the newly created activity
  6. In the event wizard for the SmartObject event, name it ‘Update Status’
  7. Select the update method for the SmartObject that you used with the ‘for each’ event
  8. Click ‘Next’
  9. For the ‘ID’ property, click assign
  10. In the context browser go to the 3rd tab (Data) and expand ‘Item references’ and then expand ‘ Loop demo reference’
  11. Click on ‘Id’ property and click on ‘Add’
  12. Click on ‘Status’ and click ‘Assign’ and enter in the text ‘Sent’
  13. Click on ‘Next’ and ‘Next’ again and then ‘Finish’
  14. Drag the remaining line named ‘Next item’ to this activity and then create a new line from this activity back to the ‘for each’ activity.

This slideshow requires JavaScript.

That is a simple example of using the ‘For each’ event. Anything that follows the ‘Next item’ line is in side the loop and has the context of the current row the loop is on. You can have multiple activities in this part and the workflow  will move on to the next item once it has completed everything in that section. You must always have a line going back to the activity with the ‘for each’ event in.

Other things to remember

  1. Choose 1 property to return in the for each event. Always best to use a primary or foreign key
  2. Remember to select ‘Return all Results that match filter’ as it will return the complete list back and it doesn’t matter if there is no filter applied.


Next step using references with the ‘For Each’ Event

So we have created a simple workflow with a simple for each loop. But what if we wanted to get more data from the for each event and then possibly use it in a line rule.

In the next example, the workflow is going to check the current status of the item it is looking at. If it’s status is already ‘Sent’ it will ignore it and move on to the next item in the list and if the status is ‘Not Sent’ it will then update the status as normal

I am going to use the same workflow as before

Creating the reference

  1. In the context browser, go to the 3rd tab (data)
  2. Right click on ‘References’ and click on ‘Add’
  3. In the ‘SmartObject Method Reference’ click on ‘Next’
  4. In name, give the reference a name , for my example i have used ‘Dummy data’
  5. In SmartObject Method, select a read type method that uses value you have selected in the for each as the input parameter. I am pointing my reference to the read method.
  6. Click ‘Next’
  7. In input mapping, click on Assign and select the id from the item reference for the for each loop.
  8. Click ‘Next’ and ‘Finish’
  9. We have now created a reference to get the related details based on the current row of the ‘for each’ event.

This slideshow requires JavaScript.


Editing the ‘for each’ line rule for ‘Next Item’

Now that we have the reference setup, we can edit the line rule for ‘Next Item’

  1. Right click on ‘Next item’
  2. Click on ‘Properties’
  3. ‘Line General Properties’ will load up. Click on  greenarrowthe green arrow for line rules
  4. Click on ‘Add’
  5.  In rule editor, select ‘And’ from ‘Boolean Operator’
  6. In ‘First Variable’ click on eclipse
  7. In the context browser,  go the references in the 3rd tab
  8. Expand References, expand your reference you created in the last section
  9. Drag ‘Status’ into the ‘First Variable’
  10. The ‘SmartObject Wizard ‘ pops up, click on ‘Status’
  11. Click ‘Finish’
  12. Select ‘<>’ from ‘Comparison Operator’
  13. In the ‘Second Variable’ enter ‘Sent’
  14. Click on ‘Ok’
  15. Click on ‘Finish’
  16. We now need to create another rule that is similar to the ‘Next Item’ rule but where the ‘Status’ is equal to ‘Sent’

This slideshow requires JavaScript.

Creating a new line rule for ‘Next Item’ and where status is equal to ‘Sent’

  1. Right click and drag a line from the ‘For Each’ activity to ‘Update Status’
  2. Then drag the line from ‘Update Status’ to ‘For Each’. (We have to do this as line can’t go back on it self without being connected to another activity first)
  3. Right click on the line and click on ‘properties’
  4. In ‘Label’ enter ‘New Item and status is sent’
  5. Click on greenarrow and then click on ‘Add’
  6. In the Rule editor in ‘First Variable’
  7. Click on eclipse and expand the process data fields
  8. Click on ‘Dummy index result’ and click ‘Ok’
  9. Select ‘=’ for the operator
  10. In Second variable enter in ‘True’
  11. Click ‘Ok’
  12. Click on ‘Add’
  13.  In rule editor, select ‘And’ from ‘Boolean Operator’
  14. In ‘First Variable’ click on eclipse
  15. In the context browser,  go the references in the 3rd tab
  16. Expand References, expand your reference you created in the last section
  17. Drag ‘Status’ into the ‘First Variable’
  18. The ‘SmartObject Wizard ‘ pops up, click on ‘Status’
  19. Click ‘Finish’
  20. Select ‘<>’ from ‘Comparison Operator’
  21. In the ‘Second Variable’ enter ‘Sent’
  22. Click on ‘Ok’
  23. Click on ‘Finish’


This slideshow requires JavaScript.


Download example here 

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