What to do when the View Variables shows an Error on a Record

[zuurg]

I've had this happen on 2 different occasions in this app I'm workin on where out of nowhere, part of it stops working saying that the Variable type is incompatible with the same variable used in other areas of the application.  This is after the code had worked properly for a while.  When I go to View Variables to see what's happening, it says Error under the variable name (both times this has happened it's been with Records.  Closing Power Apps and restarting it doesn't do anything, it still shows error (even without having run the app).  The only way to get it working again is to change all occurrences of that variable name to something different, which ends up removing the offender from the list of variables and all of a sudden, it starts working again, without having changed anything else other than the name.  

Is there a better way to destroy a variable showing an Error than to remove all references to it and calling it something new?  This most recent case wasn't too bad because it was only mentioned in one part of the app a few times, but the first time it happened was a major PITA.    Is this a bug?

[WarrenBelz]

Hi @zuurg ,

It sounds definitely like you are using the same variable name with two different structures (number/text/record etc) in different places. Use your Search to find all the occurrences and see what type of variable you are setting in each.

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[RandyHayes]

@zuurg 

This is not a bug!

If you are seeing this often, then you are working with variables in a way that is not a good one!

PowerApps has to infer its schema for all record types in the app.  To do this it has to look over every formula and determine how they all interact in order to establish the schema.

When you are doing things (potentially in your case) like :  Set(someVar, Patch(someList, {someRecord})) it will infer its schema from somelist.  If you then alter that in other places to change or add columns or types, then it gets confused...quickly!!  

9 times out of 10, you can exit the designer and then go back in and it will re-infer the schema and it will be correct.  This happens because, as you change formulas and potentially schemas, it re-infers the schema and does not forget it.  This is also another reason why some people say..."I was working on designing the app just fine, then came back to it the next day and there were errors everywhere".  This is because it was inferring the schema during design time the first time and some schema "stuck" and was good even though it was "stuck", but when re-opened, it re-inferred and that was no longer there and not "stuck" and then nothing else recognized it.

So, the moral of the story is - firstly avoid variables as much as possible and use only when really needed.  Second, try to avoid creating your own schemas if the schema is based on a datasource.  Let the datasource always be the "leader" to the schema.

Hopefully this is helpful for you.

[zuurg]

@RandyHayes ,

That is helpful and the Set(SomeVar,Patch...) is exactly the context I'm using it in.  In this case, it's only mentioned in a few places, and no changes have been made to the sharepoint list's structure.  It actually just did it again, when I was adding in a SortByColumns at the beginning of the Gallery's Items property.  When I select a record from the gallery then hit the line's edit button, it displays an Edit form in a popup.  The places where the code broke was on the edit icon (the code is Set(vMyResourceRecord,ThisItem)) and in the popupscreen's Patch code (again, using the Set(vMyResourceRecord,Patch...)

1) Is it safer to just have the EditForm's item property set to Galleryname.Selected?

2) If I get rid of the variable and point to the Galleryname.Selected instead, how can I confirm the creation of the record?  This is the code I'm using to verify it:

If(
    Not(IsBlank(vMyResourceRecord)) And IsEmpty(Errors('Resources')),
    Notify(
        "Changes Saved!",
        NotificationType.Success,
        2000
    ),
    Notify(
        "Update Failed",
        NotificationType.Error,
        2000
    )
);
Refresh('Resources')

Using the Form's SubmitForm() isn't an option here so I can't use the OnSuccess.

[RandyHayes]

@zuurg 

Well, I'm actually more zoned in on your last point - "Using the Form's SubmitForm() isn't an option here so I can't use the OnSuccess."  Why is that??  If you have a form, you should always be using the SubmitForm() method.

For #1 - you can use the gallery.selected property, however, this can lead to issues.  Your gallery will always re-evaluate its Items property whenever any changes occur to any part of it (i.e. datasource changes, a reference value changes, etc.) This will cause the gallery to reset to default.  In most cases (unless you have a Default record set in it), it will revert to the first record in the gallery...and thus, your form will have the wrong record in it!

I would say that 90% of the time I lean toward using a variable for the record selected.  i.e. Set(var, ThisItem)  Variables are snapshots of data, and in this case, it is what you want.  There are times it is not needed (if you know your gallery will not re-evaluate and reset).

For #2, get your SubmitForm to work and you will not have to worry about that and you will be able to confirm that it submitted by the form.

[zuurg]

I'd love to be able to use the SubmitForm - especially in this case since the form is pretty simple.  If it was an edit to the form, no problem.  The area that I ran into issues with was when I was trying to add a new record - there is a required field in the SP List that I didn't want showing on the form (the Project ID).  When editing, no problem because it's already there, just couldn't figure out how to get it to save for the new record.  (I can get it from the underlying gallery's SP list's .Selected.'Project ID' (it's a different list than the one the form is submitting for).

I had the field marked as not visible (but the Default was populated with the previously mentioned gallery.Selected.'Project ID') and it would still not do it and tell me the field was required.   If you have any tricks to handle that, it'll make my life much easier.    🙂