Name isn't valid. This identifier isn't recognized

[WebPortal]

My app has 2 collections:

TodosPeriodos with the months of 2020, like "Jan-2020" to "Dez-2020"

PeriodosExistentes, that it reads from the datasource, with the already existing months:

Now, I have this Form with a dropdown that works perfectly when the AllowedValues Property of the DataCard is hard-coded like:

But when Allowed Values changes to the formula below:

The drop-down does what I want: it shows only the months NOT in the PeriodosExistentes Collection:

But it returns the Error:

Name isn't valid. This identifier isn't recognized

 I could live with the error, although I don't understand it.

The main problem is that now I can't submit the form. I get another error:

The requested operation is invalid. Server response: a value must be supplied to the item.

Can anyone help?

[eka24]

The drop-down does what I want: it shows only the months NOT in the PeriodosExistentes Collection:

This is a cotinuation of what you posted earlier.

edited

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[WebPortal]

Hello again @eka24 

Yes, the data card does what it is supposed to do: it shows only the non-used-before months.

I've deleted it and inserted it again.

And again I have exactly the same errors as described:

Name isn't valid

And the form is not submitted.

[eka24]

The formula should be on the Items of Datacardvalue2 not where you have placed it

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[WebPortal]

Here we go again: I get exactly the same errors, it doesn't change anything!

[eka24]

Base on the last reply, select the Periodo_datacard2, do you have any other formula on the Periodo_datacard2?

There should not be any formula there

Please recheck.

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[WebPortal]

This is what I have:

[eka24 · Accepted solution]

Try:
DataCardValue2.Selected.Periodo

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[WebPortal]

I tried with DataCardValue2.Selected.MonthYear and it finally worked!

Thanks a lot for your help!