The value ': ' cannot be converted to a number.

[Baltner]

Hello.  I am am getting the following error the first time I load one of the screen in my app:

The value ': ' cannot be converted to a number.

Now I understand that ': ' is not a number and that Power Apps has a right to complain about this, but my problem is finding out where in the many formulas of my app this is happening. I use that string many places in the app, for example in a label like 

"Assigned To: " & assignee.Text

so that character string is all over the place. I even tried searching the fx.yaml file for that screen (after unpacking the .msapp file) but there are over 600 occurrences of ": " in the file because that's how control properties are listed (e.g., "Height: =32") and I've inspected all of them. I searched for strings like "Value(" and ".Value" and all sorts of other obvious signs that my formulas may be asking for a number, but so far have come up empty. It would be helpful if the error message provided more information about the location of the erro, like a normal stack trace, but that's not available in Power Apps. Is there a recommended way to try to solve this problem? Thanks!

[Baltner]

Update: I did manage to find the formula that triggers this error but I'm not successful in preventing it so far. It's in a gallery, and as the screen is loading (OnVisible) the app is calling a flow to get the data to create the collection for the gallery's items.  One of the properties displayed in the gallery uses this formula:

$"Priority: {Text(ThisItem.Value.priority) }"

 As a test, I changed this to: $"Priority: {10}" and the error did not occur so it seems like the app may be reacting to the fact that ThisItem.Value.priority is not defined yet and that the priority value is numeric (in the original JSON). I tried a couple of solutions like:

If(!IsEmpty(ThisItem),
    $"Priority: {Text(ThisItem.Value.priority)}",
    ""
    )

and

If(!IsEmpty(ThisItem.Value.priority),
    $"Priority: {Text(ThisItem.Value.priority)}",
    ""
    )

but this doesn't help.

Is there a way, maybe with a timer, to delay the loading of a gallery until the data that feeds it is ready?

[iAm_ManCat · Accepted solution]

Have you tried using Power Apps' Monitor tool? That will tell you exactly which control or piece of code on a control/property was trying to convert that string to a value.

If I had to guess, I would say there's a Text Input or dropdown somewhere which is using Value(Self.Text) or Value(TextInputName.Text) or if its the dropdown then Value(DropdownName.Selected.PropertyName) - this happens quite often when people try to create dynamically filled Time series, as they use (hh & ":" & mm) type format, but before it contains a value it is just ":"

So if you have anywhere you are combining values with static strings like ":" between them, I'd search for that within the Power Apps IDE as should be easy to find ":" amongst your other code

Cheers,

Sancho

[Baltner]

Sancho:

That was great advice. I had only used the Monitor in Play Mode before and the error was not occurring there. Using the setting to enable it in the published app really gave me all the information I needed, so thanks!

For future reference, if anyone were to have a similar problem, what was happening was that I was trying to set the value of 'priority' on a slider control where the value in a referenced Gallery was "Priority: X", where X could be a alue between 0 and 10. My original error-causing formula was this (in order to strip off "Priority: ") :

Right(TaskListGallery_1.Selected.priority_1,2)

and I was using 2 to allow for the two digits in "10", and that's where the error was. I replaced this with:

Switch(Len(TaskListGallery_1.Selected.priority_1),
        10,"",
        11,Right(TaskListGallery_1.Selected.priority_1,1),
        12,Right(TaskListGallery_1.Selected.priority_1,2)
)

which now handles both 1-digit and 2-digit priority values.  Dooh! As usual, the solution is much easier if you know where to look, and that's where your advice was a huge help. Thanks!

[iAm_ManCat]

Happy to help, glad it got you to where you needed!