Bug with gallery, checkbox and CountRows()

[Anonymous]

I do not know how to name this bug but here it is:

If you have a gallery which has a scroll bar, records that are not visible will not have their properties properly set until you scroll to them. This leads to some errors while using functions like CountRows in the gallery that match some specific parameter.

How to reproduce (100% reproduction rate):

Add this as static data imported from excel:

 

On a new Screen

1. Add a gallery

2. Add label and a checkbox

Label.Text:

ThisItem.Number

Checkbox.Default:

ThisItem.Value

Add a label outside of the gallery

Change Label2.Text to:

CountRows(Filter(Gallery1.AllItems,Checkbox1.Value))

Right away you will see that it is displaying the wrong result (In my case it is saying 3, even though there are 12 true values).

As I scroll the number changes.

When I reach the bottom the correct number is displayed.

If I scroll back the number is now correct:

So it seems that Checkbox is only initiated when it is visible on the screen.

To reset this and get error again simply delete the Gallery.Item and add it again and the error happens.

Would it be posible for PA team to make it show 12 right away? In this sample case the issues is easy to solve however I have one of my more complex app where it is an issue since few functions depend on the number being retuned by CountRows:

For example I have an app where people select their holidays:

It only shows the correct number when my users scroll to the bottom of the list.

Label.Text function (bold is the relevant part in this scenario):

If(
    CountRows(Filter(_VacationCollection, VacationType = "Holiday")) = 0,
    "Holidays Selected: "&CountRows(Filter(HolidayGalleryNew.AllItems,Checkbox1.Value)),
    "Holidays Selected: "&CountRows(Filter(HolidayGalleryTaken.AllItems,Checkbox1_1.Value))
)

Checkbox1_1.Default function:

If(
    IsBlank(
        LookUp(
            _VacationCollection,
            VacationType = "Holiday" && Description = ThisItem.HolidayDescription&" - Statutory Holiday"
        )
    ),
    false,
    true
)

Would anyone know a workaround from this? Much appreciated!

[FelixCuadrilla]

Hi , thanks for reaching to us.

We currently have some issues with the AllItems property in galleries, so it behaves a little erratic like you are describing.

In order to unblock you, you can change the function you are using to read the values from the data source directly, instead of the gallery like this: 

CountRows(Filter(Table1, Value))

However this may not work if you change the values on the chekboxes. If you are changing the values on the checkboxes you may want to use an edit form to update the values on the table, which will update the value on the data source. This will probably require another screen but at least will allow you to continue your work.

We are working on fixing the issue on AllItems to have it working in a future release.

[Hemanth]

HI,

In the mean time that the bug is fixed, you can use this work around if you are depending on the values checked by the user.

Use a variable to store the count of checked values i.e. on Screen.OnVisible you can use Set(HolidayCount, CountRows(Filter(Table, MandatoryHoliday = true)). This way your variable will start out with correct value. Then on each Check or uncheck of the checkbox you can do: Set(HolidayCount, HolidayCount + 1) onCheck or Set(HolidayCount, HolidayCount - 1) onUnCheck

[Anonymous]

Hi @FelixCuadrilla

Thanks for your solution it would solve the problem in the sample case however in my complex app the checkbox depends on another datasource not the one that is displayed in the gallery (thus the lookup() function). Moreover, as you said I need to keep the live number of clicked checkboxes.

Hi @Hemanth

This looks like a good solution I will look into implementing it.