New Enhancements for Dual List Box

Sometimes small changes can make a big difference. I’m creating a Configuration Helper for my Datatable component and I want the Admin to be able to select a group of fields from a list of all of the fields on an Object. The Dual List Box Flow Screen Component is perfect for this because it can be combined with the Get Field Definitions component that is included in the new Flow Base Components library.

The only problem with this list is that even though all the fields are shown, they are not in any particular order. I updated the component to allow you to specify a parameter to sort the list of fields. The options include sorting by the field label or by the field value (API Name).

This component has also received a nice Summer ’20 update with the inclusion of a CPE (Custom Property Editor).

Now my selection list for the Object fields is sorted and much easier to use.

Notify of
Inline Feedbacks
View all comments

[…] Version 2.1.3 Unlocked7/24/20 – Eric Smith – Added option to sort results from GetFieldDefinition Flow ActionRead about it here. […]


Hi Eric. I’m hoping you can help me understand an issue I’m having with this component. I am using a ‘one string collection’ variable to feed values into the component. I have mirrored the configuration that you have in the ‘Demo Flow – Dual List Box’ sample flow that was installed with the package. No matter what I do, I keep getting this error: dlbTest (Screen Component) – The input parameter “null” can accept multiple values, so the assigned value must be a flow variable with the isCollection property set to true. Here’s the rub… when I use your sample… Read more »


I looked at the Empty String idea, but I’m using a collection variable to fee the values to the component. From what I can see, you can’t assign the {!$GlobalConstant.EmptyString} value to them.
The component clearly doesn’t like my text collection variable. No matter what I do, I keep getting the same error message. I have it set up the same way as in your demo, having values assigned before the screen where the component sits. I just don’t understand why the screen in your demo works, but my screen throws the error. I’ve got to be missing something.


Fantastic. I’d love to get this to work. Give me a day and time frame and I can shoot you an invite for a Teams call. (Any day but Friday. We are busting my Mom out of her assisted living facility for the day) Just email me with the best email address to use for the invite, or you can DM me on twitter @admindesigner. I appreciate you taking the time!

Jeremy Pritchard

I had the same problem. In the end I resolved it by pasting in the field value: {!colAvailableLibraryValues} and hitting return. That then removed the {! } and accepted the value


Hi Jeremy. This did work for me using the single string collection to set the values, but when I tried it on the two string variant where you can set one set of values for the label and one set for the values, I couldn’t get it to accept BOTH collection variables. Strange, but not a show stopper. I was planning on using the single string anyway. Thanks for the workaround now I can continue my development while we wait for a permanent fix by Alex!