I am utterly confused by the new 'Events' property for components

[mgreiner79]

So I knew about the 'Behaviors' property for components. I thought it was quite nice, and have used it in my app already.

Now it has been changed to 'Events' and 'Actions'.

As far as I understand, 'Events' are functions that are provided as inputs to your component, whereas 'Actions' are functions that are Output by your component.

I want to make a form modal so that, when the user submits the form, a Patch function will be called. The Patch function must be called from the parent app (not inside the component) because it needs access to the Data Connection, which is outside of the scope of the component.

So how do I do it? I make an 'Event' property on the Component called 'onSubmit'. Then when I instantiate the component in the app, I set the 'onSubmit' function to be Patch(MyCollection, SomeRecord, SomeData). 

This seems to make sense. It is like frameworks, such as React, where a callback function is passed down to a child component, that is called when some event in the child component is triggered.

Ok, so what is with the 'return value' field in the 'Event' property? My event does not return anything. Yet I am forced to put something, so I put in an empty record. Once I do that, the function that I had set to be the callback function, all of a sudden, is replaced by an empty Record. What? Why? I thought the callback was input, and the return value is output. 

Have I misunderstood how this feature is supposed to be used? What is the purpose of the return value on the 'Events' property type? How would I event access this return value in the parent app?

Am I not supposed to be passing a function as an argument to the 'onSubmit' property?

😕 

[JorisdG · Accepted solution]

The event property should behave the same as behavior property before. It's an input behavior function. Actions are new and as you correctly pointed out are input behavior functions.

Changing any of the property signature (including return type) blanks out any formulas you've already set. That is something we're looking into avoiding for a future release. In your case it just put it as a default value of an empty record as that's your return type, you'll notice most properties throughout Power Apps have some sort of default value and not blank.

As far as the return type, you don't need to worry about it. If you're not returning anything just leave the boolean default. There is no "return" statement that would be required like you see in traditional imperative languages.

[JorisdG]

I noticed this morning the blog is now showing the old contents. Still trying to get this fixed.

[claytsch]

Is there any update on changing the behavior of clearing property values when you change the property settings in the component.  This is probably the most frustrating and time-consuming issue I have with PowerApps.  With recent updates, the properties have started throwing errors for "event" properties I left originally left as the default "Boolean" type before there was a "None" option.

To fix the errors I have to copy the properties for dozens of instances of components, change the return type to "None" then go back and paste the original property values back into the component instances.