Edit Power Apps Custom Form Overwrites Variable; Can a Context Variable be locked?

[videnoir83]

I have a SharePoint list that creates a custom unique product ID that increments on every new task.  If a person goes to edit the entry, the field with the value that it uses to calculate increments gets overwritten to blank.  I know this is because that field is set to show the value of the context variable, and when you hit edit on the form, it's clears it because it's a variable and you only need to generate the ID through the button once.  (Hope this makes sense...)  My question is, once a variable is calculated, is there a way to lock that value in the field or in another field so that it won't change every time an item is edited?  Disabling the field when a value is present doesn't work (tried that).

[Minik]

Hello @videnoir83. Question. The value which you use to calculate... is the one coming from a Dropdown/Combobox? Maybe you can give us some more details or a screenshot of the field which turns blank.

[Ethan_R]

Hi @videnoir83 ,

I'm not sure how things are setup, but I assume you are trying to generate value based on some record count or something.

If you can try to use, 

If(
   IsBlank(productID),
   //Perform Calculation
)

This will only perform calculation if ProductID is blank else it will ignore

Hope this helps

[videnoir83]

Basically, I have two columns in the SharePoint list. One called Product ID and one called Product ID Number.

In my Power App, when you hit a button the button runs functions to check for the max last value in the Product ID Number Column.  Then it adds 1 to the number and generates a unique value for the Product ID by concatenating the name of our office with that value and the fiscal year (e.g. OFFICE-0001-23, OFFICE-0002-23).

Once that is done the user saves via Submit Form, and the values populate in their respective columns; however, when you select the item, and hit Edit to update it, it removes the value in Product ID Number, therefore not allowing for incrementation to continue.  It is doing this because that field in the app is set to the name of the context variable for that value, so it's thinking upon editing, oh the context variable hasn't been initiated so the value of the field should be blank and therefore overrides the value.  I would like to be able to say, once you've pressed the button and generated the Product ID and Product ID Number, stop and freeze that value in the Product ID Number column.

[videnoir83]

Found this in the help documentation:

"A context variable holds its value until the app is closed. If you define a context variable and set its value on a particular screen, that information remains intact even if the user switches to a different screen. Once the app is closed, the context variable's value will be lost and must be recreated when the app is loaded again."

I need it to hold it's value.

[Ethan_R]

Hi @videnoir83 ,

When you are updating the Value of ProductID, as you said it takes the context variable data.

You can try the following:

You can set the context variable data based on the Form mode,

If(
  Form1.Mode = FormMode.New, 
  //Perform Calculation of new ID,
  Parent.Default
)

As when you use

NewForm(Form1) then form sets to save New Record in database

When you use, EditForm(Form1), the form sets to Edit mode meaning you are updating existing record.

Documentation

Blog

Hope this helps

[videnoir83]

Can someone provide an example piece of code for SharePointIntegration On Edit, edit form and set variable?

I have EditForm(Form2); Set(varID,......), but that doesn't seem to work, I think because I have it as two separate actions as opposed to something like, EditForm(Set(varID.........)Form2)?

[WarrenBelz]

Hi @videnoir83 ,

Firstly, SharePoint integrated forms have the fundamental flaw that unless you refresh SharePoint (refresh the browser) when changing to another record, the form is actually still open (RequestHide() does just that) and it does not run (among other things) App OnStart or Screen OnVisible. I have also found trying to set Variables on the integrated controls you mention inconsistent at best.

The only value I have found can be reliably regarded as updated is SharePointIntegraton.Selected.

But back to your fundamental question - Variables only exist while the app is being run, but I do not think that is actually what you want here (so why bother setting it in the first place) , rather simply do what @Ethan_R has suggested and set the Default of the field to your calculation when the Form is in New Mode.