pass value to front-end function(event handler)

usr338

Hi, how can i pass a value to front-end function that is used as event handler for button field? i need to share a function for multiple button field click event and pass id of nearby field to it .

gabriel

There is no value to pass. If you execute a frontend function, it works within the context of a form and can collect the desired values from it.

If you want to avoid re-collecting the same values inside different frontend functions, you can create another, shared function that does this and is called multiple times.

usr338

Let's me explain the scenario. I have multiple field with a small button nearby them.

User can type input value in field input or select value from a selection list by clicking on small button near field.

This selection list actually is a relation variable that act as data source for all input field.
There is only one selection list that can be used as selection value of multiple field ( by clicking field nearby button).
when user click the button, i need to know which field value will be replaced by value in selection list so somehow i have to pass id of filed to event handler of button to set a variable that act as pointer to current field (let name it id variable). then show the selection list.
when user select the value from list, in event handler of selection list, selected value will be set to appropriate field input(using id variable) .

gabriel

I am really sorry, but I cannot follow what you are describing.

usr338 I have multiple field with a small button nearby them.

What do you mean by this? Do you have a relationship input field (eg. attribute field, type n:m) with multiple values? Or do you have multiple, different fields that each have a button next to them?

usr338 or select value from a selection list by clicking on small button near field.

How does a user select a value by clicking on a button? A button in this context would execute a function I assume. What does the function do?

usr338 This selection list actually is a relation variable that act as data source for all input field.

Sorry, no idea. How does a variable act as a data source? Are you using the variable as a filter somewhere? Do you access it in a function?

If you mean that you need a function to be called when a variable get´s updated - you can use the field option "Function on value change" to execute a frontend function if the variable is used as relationship input.

usr338 when user click the button, i need to know which field value will be replaced by value in selection list so somehow i have to pass id of filed to event handler of button to set a variable that act as pointer to current field (let name it id variable). then show the selection list.

When a user clicks a button field, you are in control of the function being executed. In that function you have access to all field values. What do you mean by "selection list" here? If you mean the variable as relationship input, you can access the current variable value inside your frontend function via placeholder.

Please try to keep to terms used in r3 to describe your request. There are no "selection lists" - there are relationship input fields (eg. fields displaying relationship attributes) or variables presented as relationship inputs. We do not have "event handlers", we have frontend functions being executed in different contexts (form functions, button function, function call on field value change, etc.).

If we can use the same terms, it should be simpler to understand each other.

usr338

gabriel Hi, I really appreciate the time you took to respond. Thank you.
I can see from your response that I haven't been clear enough and am lost in my own thoughts. Sorry about that.
Perhaps it would be better to say that using the combination of functions and controls mentioned, I am trying to create a custom field type that accepts input from the user in two different ways: by typing a value or by selecting from a list.
The buttons next to the field have the role of changing the input mode. With one press, the field goes to the text input mode and with the next press, it goes to the list input mode.
And I wanted to use this field control for several input field (attribute field of relationships).
Given that the fields of my form that I wanted this feature to be added to were of the text type, I placed a button next to each of them so that when they were pressed and in the function related to the button, the main field would be hidden and a relationship type variable would appear to receive input and when the button was pressed again, this state would be reversed.
For this purpose, I needed to pass the field identifier to the function that is executed when the button is pressed.

gabriel

usr338
Thank you for taking the time to restate your request. I think I now understand what you want to do.

How I would approach this:

For each field input pair (eg. the text & alternative relationship input), I would have 1 extra variable.
This variable would be a boolean that I toggle between true/false when I click the button next to the input field pair.
A form state would show/hide either of the two input fields based on the current variable value (true/false).
If I need to take over any current values from the input fields (when the user toggles between them), I would do that in the function that the toggle button executes.

This means that for every input with this toggle option, you would have 2 fields (both input types, either attributes or variables used as inputs), 1 variable (to control which is visible), 1 button + function (to toggle the variable state + copy values if needed).

Variables do not need to be used as inputs and can serve many other purposes - like controlling field visibility in this case. You probably already know this, but just in case.

There is no "field identifier" that we can pass around and it´s not required for your case as I understand it. You could argue that it would be possible to reduce the number of functions maybe. Was that the reason you asked for it?

usr338

gabriel Dear Gabriel, Thank you for your time and effort. That is exactly what i did, and yes i wanted to reduce the number of function that assigned to each button.(by share function and decide what to do inside it).

gabriel

Every field has an ID, which is visible when you add it via placeholder to a frontend function and enable the preview mode in the function editor. It´s not really a supported feature, but you can pass this ID to another function and use it to address a specific field.

When you use a placeholder such as app.get_field_value({F32: ...}), {F32: ...} is replaced by the field ID. So in the end something like this is called app.get_field_value('795277ad-3eda-4e02-81b5-64ccdea4ee17'). '795277ad-3eda-4e02-81b5-64ccdea4ee17' is the field ID and could be passed to another function to be used there. So your call would look like this: app.get_field_value(myFieldId)

However, this could break in future versions, so I personally would not use it.

For future reference, your request (using r3 terms) would have boiled down to: "I want to access fields in frontend functions not through placeholders but IDs so I can reduce the number of functions I need".