ForAll on Nested Gallery

[Anonymous]

I'm using a nested gallery as a bit of a hack to get something that looks like an editable datatable with dynamic columns (see screenshot). The outer gallery represents the rows and the inner gallery (which just has a textinput in the template to act as the cell), the columns. With some jiggery pokery to get something that looks like column headers, and as long as the number of columns (items in the inner gallery) don't become too wide for the outer gallery, creating horizontal scrollbars per row, it works ok.

I'm using the textinput onchange to patch a collection that keeps track of the data until i want to save back to the datasource.

The problem I have is that the onchange event changes focus of the selected 'cell', so when the user clicks or tabs into the next cell, the event fires on the previously selected input and moves focus away from where the user wants to be. Which creates a frustrating user experience.

The ways i've thought about resolving this:

1. If PowerApps allowed programmatic control of focus, i could maybe re-set focus after the onchange event fired, but this isn't support functionality.
2. Don't use the onchange event, and let the collection go stale. This would require a means of looping through the textinputs in the inner gallery to get their values. 

With option 2, I can't seem to get access to the AllItems of the inner gallery, it is always empty. I've tried a few different permutations of nested ForAll statements, etc. but even the simple example below returns a week number (expected) and blank value (not expected) for every row of the collection (outer gallery). 

ForAll(OuterGallery.AllItems,Collect(testcount,{week: lblWeek.Text, colcount: CountRows(InnerGallery.AllItems)}));

Any suggestions?

Thanks in advance.

[v-xida-msft · Accepted solution]

Hi @Anonymous,

I have made a test on my side, and don't have the issue that you mentioned. The screenshot as below:

Set the OnSelect proeprty of the "Collect" button to following:

Clear(testcount);
ForAll(
    Gallery1.AllItems,
    Collect(
        testcount,
        {
            StudentName: StudentName,
            Count: CountRows(Gallery2.AllItems)
        }
    )
)

On your side, you should type:

Clear(testcount);
ForAll(
      OuterGallery.AllItems,
      Collect(
             testcount,
             {
                week: lblWeek.Text, 
                colcount: CountRows(InnerGallery.AllItems)
             }
      )
)

Please consider take a try to add a Label control within your OuterGallery, set the Text property to following:

CountRows(InnerGallery.AllItems)

then check if the Label control shows proper value (rather than blank).

In addition, as an alternative solution, you could consider take a try to add a Label control (called "InnerGalleryCountLabel") within your OuterGallery, set the Text property to following:

CountRows(InnerGallery.AllItems)

then modify your ForAll formula as below:

Clear(testcount);
ForAll(
      OuterGallery.AllItems,
      Collect(
             testcount,
             {
                week: lblWeek.Text, 
                colcount: InnerGalleryCountLabel.Text
             }
      )
)

If the issue still exists, please consider take a try to remove the InnerGallery from your OuterGallery, then re-add it again, try above formula I provided, check if the issue is solved.

Best regards,

Kris

[Anonymous]

Kris,

Thank you very much for your response. I've now cracked it, but...

When I recreated your steps on a new screen all worked as expected, but initially I could not get my real version working despite deleting and recreating the inner gallery and various other tests.

After much experimentation, I discovered why your steps worked, but my original didn't. The label displaying the CountRows(InnerGallery.AllItems) is the key! I'm guessing this, or any other enumaeration of InnerGallery.AllItems,  forces PowerApps to evaluate the items of the inner items in the same context as my ForAll is executing, but without this, I get the same results as I initially reported where InnerGallery.AllItems is effectively null.

Is this a bug, or expected behaviour?

Thanks again

[cl0wn]

Thanks Kris and Anonymous,

I had exactly the same issue until I added the label to the outer gallery as well.

Is there any word on if this is expected behaviour or a bug?

Thanks

[Joorge_c]

Hi @v-xida-msft 

What if I need all sub gallery Items collected? Not just a count of rows. Can this be done? Im currently stuck.

Tried many variations of code, but below quick sample collects 0 items.

Gallery1 being parent, Gallery2 is the sub/nested.

Clear(ColTest);
ForAll(Gallery2.AllItems,
Collect(ColTest,Gallery2.AllItems))

 Thank you

[Riyaskhan]

These issue resolved or not