CDS Business Rules Validation in Canvas Apps

[CNT]

I have created some Business Rules in CDS to validate certain fields in an entity and show error message in the Canvas App. When the Form is submitted It does a server round trip and shows the error message. BUT I would like the validation to be done on the App when the user leaves that field and the error message to be displayed in the error label in the Data Card. How to do this? Any help and tips would be much appreciated.

Thanks.

[WarrenBelz]

Hi @CNT ,

You could set a test on the OnChange property of the control to see if whatever the rule is applies.

A Notify banner is probably better, but you could also set a Variable for each control test

If(
   Whatever test,
   UpdateContext({vError1:"Whatever error message"}),
   UpdateContext({vError1:""})
)

The Text property of the Error box then could be vError1

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[v-yutliu-msft]

Hi @CNT ,

Do you want the error message that you designed in CDS Business Rules display in the error label in the Data Card?

If so, I suggest you try Errors function.

After a data function executes, you can use the Errors function to obtain the details of any errors.

Then display the data that Errors function generated.

I've made a similar test for your reference:

1)set the submit button's OnSelect:

SubmitForm(Form6);ClearCollect(a,Errors(entityname))
//I use form6 to update the entity, please replace with your form name and entity name

Then the error message will be saved in a collection, you just need to display the data of the collection in the error label in the Data Card.

2)UnLock the datacard

insert a label inside the datacard

set the label's Text:

First(a).Message

Then the error message will display in this label.

What's more, the disappearing time of error message can not be changed. This is system settings.

Here's a doc about this function for your reference:

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

Best regards,

[CNT]

Hi @v-yutliu-msft and @WarrenBelz 

Thanks for the ideas. But I was under the impression that by using CDS and putting all the validation logic in CDS, you don't have to do that in every App. That logic is applied to every App you make based on that entity and that the error will be automatically handled. I thought the error will be handled when you leave the field and does not have to wait for SubmitForm(). 

From the solution you had suggested, we have to write code to do this in every App. Is that the only way forward?

[WarrenBelz]

Hi @CNT ,

I am a SharePoint user, so will leave you with @v-yutliu-msft here.