Change Value within one row ONLY in Gallery

[AlexNW]

I'm trying to have an app that just takes a gallary and lets a user change a simple value as a scratch paper. I have a label inside a the gallery and using 2 buttons to add or subtract 1 from the label. 

I'm using Set(LabelVariable, LabelVariable + 1) for the button function and nothing changes... what am i doing wrong?

 

[v-yamao-msft]

Hi AlexNW,

After you configure the set function on a Button’s OnSelect property, you also need to set the Label’s Text property with LabelVariable.

Then when you click the button, the number in the Label will be changed.

However, I am afraid it won’t work for your scenario.

No matter which data source you are using, please add a column for LabelVariable in the data source.

On the app, you will need to add another screen.

On the new screen, add a label and set its Text property as Gallery1.Selected.name.

Then add two buttons, use the function Set(LabelVariable, LabelVariable + 1), add another label and set its Text property as LabelVariable.

Besides, you will need a Save button to save the data to data source with the changes you have made. You may consider to use Patch function in this case.

After you patched the changes to data source, refresh the gallery, it will be displayed on the Gallery screen for selected item.

Please try it on your side and feel free reply if you need more help.

Best regards,
Mabel Mao

[Anonymous]

Hi Mabel Mao,

Are you saying it isn't possible to dynamically change a label, or any property of a specific gallery item?

For example, imagine I have a post with likes. How do I click the like button and automatically change the counter of likes; change the color of the text; and change the text of a label....inside that gallery item, and without refreshing the control.

I couldn't do this with a local variable, using UpdateContext, because nothing is changed visualy, in the item.

I could do something with a Collection: getting my items to a global collection, with Collect and ClearCollect, I can change variables. But then right after I click the button the gallery scrools automatically to the top of the gallery. How can I do this: like a post from the posts feed, directly?

Thank you,

luis

[JRaasumaa]

---

@Anonymous wrote:

Hi Mabel Mao,

Are you saying it isn't possible to dynamically change a label, or any property of a specific gallery item?

For example, imagine I have a post with likes. How do I click the like button and automatically change the counter of likes; change the color of the text; and change the text of a label....inside that gallery item, and without refreshing the control.

I couldn't do this with a local variable, using UpdateContext, because nothing is changed visualy, in the item.

I could do something with a Collection: getting my items to a global collection, with Collect and ClearCollect, I can change variables. But then right after I click the button the gallery scrools automatically to the top of the gallery. How can I do this: like a post from the posts feed, directly?

Thank you,

luis

---

What @v-yamao-msft said it the best solution. Adding a column to increment will work but putting a variable that changes into a gallery results in every line of the gallery containing the exact same variable and value.

Gallery items are a single row of a collection or data source, a variable in the list doesn't have a unique row to reference, it's going to be the same everywhere.

[Anonymous]

Hi

Actually, what @v-yamao-msft said as the best solution was to create another page to edit the value and when going back, refresh the gallery. He also mentioned a context variable where he could set a value and use that inside the gallery. That wouldn't work since there needs to be individual values per gallery item.

Both of that solutions aren't the best. While finding out the possible solutions I came up with a better solution.

Basically, instead of putting a list of items in a local variable using UpdateContext and apply that in the gallery, or using the list directly in the gallery Items property, what you should do is:

• Put the list of items in one Collection (aka. Coll1), using Collect(..), or ClearCollect(..)
• Transform Coll1 as you please: adding columns, adding dinamic items, etc.
• Create a reference Collection, from Coll1, in Coll2 using Collect(..), or ClearCollect(..)
• Apply Coll1 as the Gallery Items
• On each edit control that needs to change on the spot, you make the formulas of that control dependent of Coll2 and all the fixed information comes from Coll1:
  • for example, Labels containing text/html may be fixed and do not change...so it is connected to the gallery using ThisItem.bodyText
  • now imagine the likes example, when you click a button the likes counter increases by 1. You get this data from Coll2 using Lookup(..) method.
• When something changes, you change it in Coll2.
  • For example, you increase the likes counter in Coll2

The problem here is that you need to maintain both collections synced. This means that when you click like (in this example) you need to add a like in the origin of the list. In my case I have a Custom API connector and, after calling the API to add a like, I change Coll2 to change in the UI.

This means that when I refresh the datasource, the like is there and you can collect Coll2 from there, since it is synced.

Why not use a single Collection and use Patch or UpdateIf in there?!! Because when you do that and change something, in powerapps, the collection (not the gallery) changes its focus to the first item, always. That means that if I'm way down scrolling the gallery and do a like...it scrolls back to the top, regardless. The solution for this is to change in Coll2 and keep Coll1 unchanged, unless we get all items again, with a refresh.

The concept is more complex to explain in writing than it actually is. So I hope I was clear in this explanation.

BR,

Luis

[JRaasumaa]

---

@Anonymous wrote:

Hi

Actually, what @v-yamao-msft said as the best solution was to create another page to edit the value and when going back, refresh the gallery. He also mentioned a context variable where he could set a value and use that inside the gallery. That wouldn't work since there needs to be individual values per gallery item.

Both of that solutions aren't the best. While finding out the possible solutions I came up with a better solution.

Basically, instead of putting a list of items in a local variable using UpdateContext and apply that in the gallery, or using the list directly in the gallery Items property, what you should do is:

• Put the list of items in one Collection (aka. Coll1), using Collect(..), or ClearCollect(..)
• Transform Coll1 as you please: adding columns, adding dinamic items, etc.
• Create a reference Collection, from Coll1, in Coll2 using Collect(..), or ClearCollect(..)
• Apply Coll1 as the Gallery Items
• On each edit control that needs to change on the spot, you make the formulas of that control dependent of Coll2 and all the fixed information comes from Coll1:
  • for example, Labels containing text/html may be fixed and do not change...so it is connected to the gallery using ThisItem.bodyText
  • now imagine the likes example, when you click a button the likes counter increases by 1. You get this data from Coll2 using Lookup(..) method.
• When something changes, you change it in Coll2.
  • For example, you increase the likes counter in Coll2

The problem here is that you need to maintain both collections synced. This means that when you click like (in this example) you need to add a like in the origin of the list. In my case I have a Custom API connector and, after calling the API to add a like, I change Coll2 to change in the UI.

This means that when I refresh the datasource, the like is there and you can collect Coll2 from there, since it is synced.

Why not use a single Collection and use Patch or UpdateIf in there?!! Because when you do that and change something, in powerapps, the collection (not the gallery) changes its focus to the first item, always. That means that if I'm way down scrolling the gallery and do a like...it scrolls back to the top, regardless. The solution for this is to change in Coll2 and keep Coll1 unchanged, unless we get all items again, with a refresh.

The concept is more complex to explain in writing than it actually is. So I hope I was clear in this explanation.

BR,

Luis

---

Actually @Anonymous, what @v-yamao-msft said in part of his solution was to add an additional column to assist with keeping track of the value and is exactly what we do in multiple app screens to great success. It does not scroll to the top on refresh of the gallery, it keeps it's position on the screen and works wonderfully.

This can all be solved by using a Patch command on the + and - buttons that updates the column value, and then a ClearCollect of that new data that is displayed in his Gallery.

It's short, sweet, and simple and would absolutely get the job done.