Radio button OnSelect sometimes not working

[Lexicron]

This is a survey app. Users select radio buttons ranging from Strongly Disagree to Strongly Agree. There are multiple pages of questions.

I have a Gallery, the items are questions, and each item/question has a Radio control. The Radio OnSelect action collects the question number and the radio selected value into a Collection. The Collection has 2 columns, Q and ResponseValue, where Q is the question number.

Radio.Onselect:

If(
    !IsEmpty(Filter(Collection, Q=Text(ThisItem.QuestionNumber))), //already answered, want to change answer
        UpdateIf(Collection, Q=Text(ThisItem.QuestionNumber), {ResponseValue:Radio.Selected.Value}), //changing answer
    //else
        Collect(Collection, {Q: Text(ThisItem.QuestionNumber), ResponseValue:Radio.Selected.Value}), //saving first answer
);

If you're changing an answer, update the answer in the Collection. If you're answering for the first time, just collect the answer. 

My problem:

• Updating an answer always works, for all questions, for all pages
• Saving a first answer sometimes works
• Saving a first answer sometimes doesn't work
  • When it doesn't work, it's always the topmost question of a page

Say I have 10 questions in total, 4 questions per page, displayed in order of question number.

1. Page 1 has Q1-Q4,
2. Page 2 has Q5-Q8,
3. Page 3 has Q9-Q10.

Sometimes everything will work and I get to collect all 10 answers. Sometimes 1, or 2, or 3 answers will fail to collect. When this happens, they are always one of these 3 questions: Q1, Q5, Q9, because these are the ones that appear at the top of their respective pages.

I don't understand why. I've rewrote the OnSelect multiple times, but this bug still comes up every now and then.

I mentioned there are multiple pages of questions. Here's how I handled it:

I had to hardcode the paging. I know what questions I want to show on each page. I created a collection for each page: Page1, Page2, Page3. These collections have 2 columns, QuestionText and QuestionNumber. At the start of the app, I run multiple ClearCollects to setup my paging:

1. Collect QuestionText and QuestionNumber where QuestionNumber >=1 and QuestionNumber <=4 into Page1
2. Collect QuestionText and QuestionNumber where QuestionNumber >=5 and QuestionNumber <=8 into Page2
3. Collect QuestionText and QuestionNumber where QuestionNumber >=9 and QuestionNumber <=10 into Page3

My Gallery.Items has a conditional statement:

If(
    PageNum=1, SortByColumns(Page1, QuestionNumber, Ascending),
    PageNum=2, SortByColumns(Page2, QuestionNumber, Ascending), 
    PageNum=3, SortByColumns(Page3, QuestionNumber, Ascending)
)

The Survey screen that shows the Gallery has an OnVisible statement: Set(PageNum,1). The Next Page button has an OnSelect action: If(PageNum<>3,Set(PageNum, PageNum+1),Navigate(SurveyCompletedScreen))

I don't know why the Radio.OnSelect fails sometimes but not all the time. And I don't know why when it does fail it's always in the same way. I've wracked my brains over this for 2 weeks. I think I've exhausted my capabilities. Would anyone be kind enough to offer a fresh eye on this situation please?

[v-xida-msft]

Hi @Lexicron ,

Currently, I could not reproduce your issue on my side. As an alternative solution, please consider take a try with the following workaround:

Set the OnStart property of the App to following:

Collect(Collection, {Q: "", ResponseValue: ""});
Clear(Collection)

Set the Items property of the Gallery to following:

SortByColumns(
              If(
                 PageNum = 1
                 Page1,
                 PageNum = 2,
                 Page2,
                 PageNum = 3,
                 Page3
              )
              QuestionNumber, 
              Ascending
)

Set the OnChange property of the Radio control within your Gallery to following:

If(
   IsBlank(LookUp(Collection, Q = Text(ThisItem.QuestionNumber))),
   Patch(
         Collection,
         Defaults(Collection),
         {
            Q: Text(ThisItem.QuestionNumber),
            ResponseValue: Radio.Selected.Value
         }
   ),
   Patch(
         Collection,
         LookUp(Collection, Q = Text(ThisItem.QuestionNumber)),
         {
           ResponseValue: Radio.Selected.Value
         }
   )
)

please take a try with above solution, then re-load your canvas app (fire the OnStart property of App), then check if the formula is working well in your canvas app.

More details about the Patch function, please check the following article:

https://docs.microsoft.com/en-us/powerapps/maker/canvas-apps/functions/function-patch

Best regards,

[Lexicron]

Thank you @v-xida-msft. I have changed my code to yours but the issue still happens.

The problem is always the topmost question of the page. I have tested by answering out of sequence, e.g. answering Q3 then Q2 then Q1, and it's always Q1 at the top of the page that is affected, if at all. I have also tested by skipping to the last page of the survey and answering backwards from Page 3 to Page 2 to Page 1, and the issue is still there.

I think it may have something to do with the paging? Something about how the Gallery items are being switched in the IF statement when the Back and Next buttons do PageNum-1 and PageNum+1. But I don't know why only the first item in the Gallery gets this issue 😞 

I do have a Radio.Default code that I forgot to mention! The users of this app are allowed to save their survey and continue another time, so I have to load their saved answers. To do that, I have a Load button that looks up the record and collects the responses into the same Collection. Then I have the Radio.Default set to

If(
    !IsEmpty(Filter(Collection, Q=Text(ThisItem.QuestionNumber))),
        LookUp(Collection,QuestionNum=Text(ThisItem.QuestionNumber)).ResponseValue,
    ""
)

Another thing I wasn't upfront about: My Radio items are 10001, 10002, 10003, 10004, 10005, instead of Strongly Disagree, Disagree, Neutral, Agree, Strongly Agree. This text is actually in a label at the top of the page, and the radio buttons have their text set to transpaprent. The items are 5 digits each because I needed the radio circles to be spaced out correctly to line up underneath the Disagree/Agree text in the label at the top. HOWEVER, my response values need to be 1, 2, 3, 4, 5 as they are used to calculate a survey score when the user submits. Therefore, in all my code where there is Radio.Selected.Value, it is actually a Switch statement.

Switch(Radio.Selected.Value, 10001, 1, 10002, 2, 10003, 3, 10004, 4, 10005, 5)

For Radio.Default it is also a Switch statement in reverse. However, I don't think this should have any effect?

I don't think it's failing the IF statement in the Radio.OnChange. It's more like the OnChange doesn't get triggered at all. Because otherwise if it is actually reading the OnChange code then even if it fails the IF statement it will still do the last thing in the statement, right? It should still collect something. So this makes me even more sad now because it means it doesn't matter how I change the OnChange code, if it doesn't even get read at all. Oh noooo

[Lexicron]

This is the problem:

The radio circle for "Neither" is selected, but the canvas is not detecting a selected value! I have a label with Text set to Radio.Selected.Value but it is blank, even though you can see that there IS visibly a selected value in the Radio control.

[v-xida-msft]

Hi @Lexicron ,

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

Please take a try with the following formula:

Radio.SelectedText.Value

Also please check if you have reference selected value from proper Radio control. Make sure the Radio control which you selected values from is exactly the "Radio" you referenced in your Label Text property.

Best regards,

[Lexicron]

Hi @v-xida-msft 

Sorry, I think I was premature on calling out that bug. I can't replicate it anymore.

On the other hand I used another test and I think it's a different bug. I removed the entire OnChange code and also the entire Default code, and in OnChange I just put in:

Set(varTest, ThisItem.QuestionNumber)

So that is the only thing the radio control does.

Then I added a label (outside the gallery), with Text property

varTest

So with every question answered, the label should update with the current question answered. If I answer Q1, Q3, Q4, Q2, the label should change from 1 → 3 → 4 → 2.

However sometimes the label will not update even though a question was just answered. For example I will answer Q1, Q3, Q4, Q2, but the label will only show 1 → 3 → 2 because it didn't recognise that Q4 was answered. I tested this sequence 50 times. This bug doesn't always happen. 26 times it showed 1 → 3 → 4 → 2 correctly, 20 times it skipped 4, 3 times it skipped 1, and 1 time it skipped 2.

I can only conclude that - on some occasions - the OnChange doesn't trigger.

[v-xida-msft]

Hi @Lexicron ,

Currently, I could not reproduce your issue on my side. Based on the issue that you mentioned, I think this issue may be related to Radio control itself.

Which version of PowerApps do you use? The latest version (3.20043.21)?  Please consider take a try to edit your canvas app using previous version of PowerApps, then check if the issue is solved.

Please check my response within the following thread:

https://powerusers.microsoft.com/t5/Common-Data-Service-for-Apps/Issues-in-CDS-Lookup-references-for...

On your side, please go to "PowerApps Canvas app Create" guide panel, then switch to "Account" setting-> "Change Authoring Version" option-> "Authoring Version" to previous version.

Or you could access previous version of PowerApps through the following link directly:

https://create.powerapps.com/v3.20023.8.147468054/studio/

Best regards,

[Lexicron · Accepted solution]

I have found the problem. There is a glitch relating to how the Radio control's Default property and OnChange property work tgoether. Without the Default property, everything works 100% of the time. With the Default property, OnChange works about 90% to 99% of the time. The other 1% to 10% of the time OnChange fails to trigger regardless of what code is in it.

I am keen to call this a bug because it doesn't just fail 100% of the time. If it did then I can accept that it is a limitation of the PowerApps platform that Default and OnChange will interfere with each other (as is the case for the Slider control), but the fact that it works most of the time but not all the time is very suspect. It makes the radio control unreliable.

Good news is I have found a workaround for this. Remove all code in the Default property, and in lieu of that, insert Circle icons and make them black dots, just like the selection dots in the Radio control. I have 5 items in my radio control, so I made 5 dots and placed them over the circles. I have a Label per Item in my gallery set to Text : Lookup(Collection, Q=Text(ThisItem.QuestionNumber)).ResponseValue.

For each dot icon, I made their Visible property tied to what is in Label.Text. Dot1 is visible if Label.Text="1", Dot2 is visible if Label.Text="2", etc. This way my Radio OnChange works to collect responses, and when I need to see what I'd answered before, instead of using the Radio Default, the dot icons will work to populate my previous responses.

[BlueChip]

I faced the same issue, and came up with a very easy solution:

Attach a toggle to the radio-control and point to that toggle's value instead of directly to the radio.selected.value.

[henningjp]

@BlueChip  Can you explain this a little further?  I'm not seeing how this helps.