Patch Resets App

[cwebb4]

Hi everyone, 

I have run into an issue with a Power App that I am building for my dept.

App Interface: Scrolling list of names on the left side. Select a name and the specific gallery to that user is brought up with their information, a few checkboxes, and text inputs. Choose another name and it is the same gallery but with information tied to them, all stored in a Sharepoint list. 

The goal: For the checkboxes/text inputs to save for each user and I have successfully done so using the patch function. All of the data is updated and saved in Sharepoint and reflects that on the app.👍

The issue: After I click a checkbox, it updates and then it 'resets' the app. After a few seconds the app will go back to the first person in my scrolling gallery. This is quite the annoyance because often times I will want to update more than one box or text input, but I have to search for the person again and click on their name to bring up their specific page again. Is there a better way to achieve my goal or a different function that I can run to make the process more efficient?

The Code (for checkbox): 

On Select - 

Patch('Onboard List',
ThisItem, {ChkCC:
("Yes")})

On UnCheck - 

Patch('Onboard List',
ThisItem, {ChkCC:
("No")})

Default -

If(ThisItem.ChkCC="Yes",true,false)

[RandyHayes]

@cwebb4 

Keep in mind that PowerApps is just like Excel...when you update something that a formula depends on, that formula will re-evaluate.  In your case, you are updating the datasource that your Gallery Items property relies on so the gallery formula re-evaluates and the Gallery selection changes back to the Default property value...which you probably have as blank.

Now, in many cases this does not have to happen IF the Items property formula is not complex.  Complex (in the case of PowerApps) means anything that includes a Sort, a Search, Data Shaping (AddColumns, etc.).  So, if your formula for items includes any of that, it WILL re-evaluate.

Things you can do:

1) Consider doing all the changes in a batch rather than one-by-one

2) Simplify your Gallery Items property

3) Use a snapshot of the Table/DataSource (a variable) for the Items property. 

If you need assistance on any of the above...just let me know.

I hope this is helpful for you.

[cwebb4]

@RandyHayes 

Thank you for the quick response! This makes sense as I am using a Search function in the formula for my Items property. 

I was hoping to stay away from option 1, but it seems like it will be the most practical for my project. If you know of any documentation for #3 that you could lead me to it would be super helpful. Thank you.

[RandyHayes · Accepted solution]

@cwebb4 

I don't have any particular reference for #3 other than to provide details on how to do it.  

Using that option is going to be dependent on how you want information to be "current" on the screen - because it is a snapshot and will be up-to-date only at the point that you take it.

A fourth option is to use a collection (as it is a variable/snapshot that you can update easily).  You would then need to double your update - one for the datasource and one for the collection.

However with all of these, the primary goal is to simplify the Items property of the gallery so that it does not need to re-evaluate.  If it does, then the situation you have now will still exist.

You can also play with the Default property of the gallery to keep the record current in the gallery, but it does provide a little bit of a "jerky" look to it.  However, it will keep you in the general area of the selected item.

The trick for this would be to set a variable to the selected record, and then use that variable in the Default property of the gallery.  As long as you're only doing search in the items and not any data shaping functions, the gallery will keep the default record shown and selected.