Process parameters initialization issue

RE: Process parameters initialization issue

Mike Schmitt — Wed, 06 May 2020 14:31:58 GMT

Generally it would only be really relevant to your start form here due to the variable being initialized to Zero by Appian. In other places that wouldn't necessarily occur, though if there were a chance for a 0 value to be passed to a dropdown in a similar manner, a similar "zero check" in the code would also be beneficial.

RE: Process parameters initialization issue

ivanm0004 — Wed, 06 May 2020 14:19:44 GMT

This start form part confused me, because I understood it as this handling is only meant for this specific process and not for general "0 case" handling on my interface (which I can also reuse in other processes).

Thx for the clarification 🙂

RE: Process parameters initialization issue

Mike Schmitt — Wed, 06 May 2020 13:55:00 GMT

[quote userid="46508" url="~/discussions/f/new-to-appian/18780/process-parameters-initialization-issue/73859"]

it means that my dropdown is trying to fetch employee with ID = 0 for it's default value and fails to do so as I don't have one with that ID?

[/quote]

Basically. Read the error message you put in your screenshot. In it, it says the value you're trying to pass is 0, while the choiceValues array is a list of non-zero values. This is a basic requirement of Dropdown Fields - the only exception they can handle is when the Value is "null()", and even then only if you have a placeholderlabel defined.

[quote userid="46508" url="~/discussions/f/new-to-appian/18780/process-parameters-initialization-issue/73859"]Or somewhere in the interface code[/quote]

To be fair, I believe i did say "on your start form interface ...the value..." above, though my wording may have been less clear than I imagined it was. So in other words, here:

RE: Process parameters initialization issue

ivanm0004 — Wed, 06 May 2020 13:47:18 GMT

Ok, it means that my dropdown is trying to fetch employee with ID = 0 for it's default value and fails to do so as I don't have one with that ID?

Also, I'm not sure if I understood your solution correctly:

You mean to put your IF statement here?

Or somewhere in the interface code?

RE: Process parameters initialization issue

Mike Schmitt — Wed, 06 May 2020 13:36:17 GMT

By default, integer PVs initialize with a value of 0 (zero), not null. That would explain the issue in your dropdown. Within your start form interface, fixing this would be as simple as wrapping the value in an if() statement, like value: if(ri!selectedEmployee = 0, null(), ri!selectedEmployee)