Dear ,

This is the apporach i used to solve this , hope it helps ur scenario 

First off , create a layout consists of 1 drop-down-list , 1 txtbox , 1 datalabel

Go to the data labels properties and add an expression to it as the following 

As for the configuration for ur Transfer data is as the following 

Note : notice in picture number 3 im using the "display" attribute , just incase u needed the value not the display , u could just change the display usage into the value in picture number 3. 

Hope it helps!

Best regards.

I'm in the need for this scenario in a similar fashion.
I'm doing a lookup on an AD Group to populate the names of the individuals in the AD Group - but I need to display the list in a concat fashion not a list.  (Cleaner look)

I've gotten it to populate a List Box but now trying to use an expression to show all the values. 

I'm using the K2 AD User Explorer List By Group Method.  Filtering in a value of the AD Group Name to filter the users.

With the instructions / screen shots below I can't get it to populate the Data Control or the Text Box.

My steps on the View / Form -  populate a data control with the AD Group Name - then run filter on the SMO to populate the List Control.  

I even tried using a Drop Down Box - same rules as shown (slightly modified) but still not working.  Tried putting the For All items on the drop down after changed.  After the List Box was populated.

Any help on this that would be AMAZING!  Thanks!