Dynamic List Box Not Populating Correctly

[emorales96]

Hello,

I am looking for help. I currently have a Chained App as follows:

1. Chain App 1: User selects the input files (3 files) for analysis --> these input files are exported as .yxdb files (File 1,2,3)

2. Chain App 2: Performs analysis on a monthly basis based on the files uploaded --> Files 1,2,3 are inputted and once the analysis is complete an output is generated (Analysis.yxdb)

3. Chain App 3: User selects the analyzed months for output generation (for our purposes, we do not need to see every month) 

I'm having an issue with Chain App 3. 1&2 are fine and functioning correctly.

I tried creating a list box to be dynamic based on the the file the user inputs since the months of analysis can differ widely. However, my list box isn't updating based on the uploaded user files. When I click run workflow on Chain App 3, that's the only time it'll refresh the dates. Any idea that I'm missing? Unfortunately I can't upload my workflow for security reasons.

[caltang]

Are you doing it like this?

Only then it will update. Ensure that your field headers are the selection fields.

[emorales96]

This is how my workflow looks right now.

I don't think I can use a filter since the fields are months (ex: 06/30/2025)  or can I?

[apathetichell]

@emorales96 --- so a chained app is good and the correct approach here. What you should be doing is:

app 1--- creates a name value pair --- this is going to be the listbox field and value --- they can be the same. this is going to create a static file/file location. It takes in a dynamic file (file browse tool)---> it also will pass in the file data to app 2--- you may write that out to a .yxdb at a predefined location.

app2 --- this will take in the DATA from the file from app 1.  1. It will have the listbox --- which will reference a static file. The static file. will be list the fields.

if this is date time --- I would recommend using a hash like datetimeformat([datefield],'%Y-%b') in your app 1.

you apply this same conversion in your filter tool with datetimeformat([datefield],'%Y-%b') in ('2025-Dec')

your listbox tool is set to listmode with "    ","   " as the delimiters

your action tool replaces a specific string. It connects to the filter tool and replaces '2025-Dec'

[apathetichell]

Note --- the above is the basic flow logic --- I notice you have 3 apps so you'll have to adjust. There's a tire size weekly challenge which shows you how to chain apps --- see: https://community.alteryx.com/t5/Weekly-Challenges/Challenge-175-Tire-Size-Calculator/m-p/447639 --- you can try downloading some of the solutions as .yxzp and reverse engineering.

[caltang · Accepted solution]

I don't see why not. Perhaps you need to make it an active file selection and hook it up to the list box either through my method or with the NAME && VALUE file method. 

https://knowledge.alteryx.com/index/s/article/Dynamically-Create-List-Box-Values-From-Input-File-158... This helps.

[KGT]

@emorales96, Remove the select tool from the app in your screenshot. You can't have normal tools before interface tools. The list box will feed Metadata from the Input Tool, but not with the Select in the road.

The interface tools will initialise before any of the other tools run.

[apathetichell]

@KGT @caltang --- did the tools behavior change? my memory is that the listbox will be cached to the last workflow run (not app run). If that's still the case --- that article really should be updated to explain how to do that via chained apps. 

@KGT you can have have normal tools before interface tools. the column names will still be used to populate the listbox when run on designer and the the next app run will reflect the selections from the select tool. If this isn't the case then my seven month vacation from Alteryx has led to some serious atrophying.

[KGT]

@apathetichell, you are correct that it will cache the metadata, however that will be from the last time it was run and then saved, it'll be the cached on the select, not the listbox. And there is no guarantee on that, it's only if it's a tool that stores the metadata in the workflow XML (which Select does), basically it's a happy accident that it works. In this case, the first thing I would do is remove the select. 

I skipped a step there, and listed a best practice as standard rule. As the selection won't change, the select is pointless, and the "selection" should be put into the Interface tool. So, yep, it will cache, but it's just generally something I will always advise against using unless someone understands that it may be an issue..

The risk is that, when running this on designer, there is full control and as you change things it will update as the metadata is caching in the designer, but once loaded on Gallery (or as the 3rd chain), it will be persistent. It also brings in other risks like the chance that "Dynamic/Unknown fields" is not selected and so new fields don't move through.

Possibly I'm wrong and it will make no difference, but considering it works by itself, but not in the chain, I would definitely look at it. 

By the way, this is getting pretty annoying writing responses and then having to space them (or cut/paste to the end) so that I can see them... No idea whats wrong with community that the scrollbar moves to the top on every keystroke...

[apathetichell]

@KGT  --- 100% - not checking  "Dynamic/Unknown fields"  in the select tool is a huge mistake. I see it potentially useful in a situation where you want certain fields omitted from the listbox In this case (say recordID) --- if the field is there it's dropped --- and if not - no major issue.

And yes ---> run and saved on designer, vs just run. But the core problem remains and that KB article really needs edits ---> because interface tools are loaded at the same time, the file browse and listbox tool are loaded when running and the choices provided by the listbox do not update when a file with a new schema is selected. 

re: 

By the way, this is getting pretty annoying writing responses and then having to space them (or cut/paste to the end) so that I can see them... No idea whats wrong with community that the scrollbar moves to the top on every keystroke.... --- yes. terrible. thought it was just me. or mozilla or something.