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oblomov-dev merged 2 commits into from
Sep 15, 2026
Merged

Simplify event argument API: use arg instead of t_arg #325

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3f88e32
The invoices app sends its one event argument with arg, not t_arg
claude Sep 15, 2026
e2d18d4
The event-argument pages send one value with arg
claude Sep 15, 2026
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20 changes: 11 additions & 9 deletions docs/cookbook/event_navigation/backend.md
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Expand Up @@ -33,12 +33,14 @@ METHOD z2ui5_if_app~main.

ENDMETHOD.
```
If the backend needs more details about the event, use the `t_arg` parameter to add extra info. Three prefixes are available:
If the backend needs more details about the event, use the `arg` parameter to add extra info. Three prefixes are available:

- **`$source`** — the UI5 control that fired the event (e.g., `${$source>/text}` returns the button text)
- **`$parameters`** — the event parameters defined by the UI5 control (e.g., `${$parameters>/id}` returns the element ID)
- **`$event`** — the UI5 event object itself (e.g., `$event>sId` returns the event type like `press`). Note: unlike the other two prefixes, `$event` is written without the `${...}` wrapper and without a leading `/` — see the [Event](#event) section below.

`arg` carries one value, which is what most events need. For two or more, use `t_arg` instead and pass them as a table — ``t_arg = VALUE #( ( `${$source>/text}` ) ( `${$parameters>/id}` ) )`` — and read them back in the same order with `client->get_event_arg( 2 )`, `( 3 )` and so on. The two are the same wire: `arg = x` is exactly ``t_arg = VALUE #( ( x ) )``.

For details, see the [UI5 docs on event handler arguments](https://openui5.hana.ondemand.com/#/topic/b0fb4de7364f4bcbb053a99aa645affe) and sample `Z2UI5_CL_SMP_APP_167`.

## Source
Expand All @@ -56,9 +58,9 @@ METHOD z2ui5_if_app~main.
)->tag( `Button`
)->a( n = `text` v = `post`
)->a( n = `press` v = client->_event(
val = `BUTTON_POST`
val = `BUTTON_POST`
" reads the button text → result: "post"
t_arg = VALUE #( ( `${$source>/text}` ) ) ) ).
arg = `${$source>/text}` ) ).

client->view_display( view->stringify( ) ).

Expand All @@ -85,9 +87,9 @@ METHOD z2ui5_if_app~main.
)->a( n = `id` v = `button_id`
)->a( n = `text` v = `post`
)->a( n = `press` v = client->_event(
val = `BUTTON_POST`
val = `BUTTON_POST`
" reads the event parameter 'id' → result: "mainView--button_id"
t_arg = VALUE #( ( `${$parameters>/id}` ) ) ) ).
arg = `${$parameters>/id}` ) ).

client->view_display( view->stringify( ) ).

Expand All @@ -113,9 +115,9 @@ METHOD z2ui5_if_app~main.
)->tag( `Button`
)->a( n = `text` v = `post`
)->a( n = `press` v = client->_event(
val = `BUTTON_POST`
val = `BUTTON_POST`
" reads an event-object attribute → result: "press"
t_arg = VALUE #( ( `$event>sId` ) ) ) ).
arg = `$event>sId` ) ).

client->view_display( view->stringify( ) ).

Expand Down Expand Up @@ -157,8 +159,8 @@ CLASS z2ui5_cl_app_hello_world IMPLEMENTATION.
)->tag( `Button`
)->a( n = `text` v = `post`
)->a( n = `press` v = client->_event(
val = `BUTTON_POST`
t_arg = VALUE #( ( `$` && client->_bind( name ) ) ) ) ).
val = `BUTTON_POST`
arg = `$` && client->_bind( name ) ) ).

client->view_display( view->stringify( ) ).

Expand Down
4 changes: 1 addition & 3 deletions docs/cookbook/expert_more/value_help.md
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Expand Up @@ -116,9 +116,7 @@ CLASS z2ui5_cl_sample_f4 IMPLEMENTATION.
)->a( n = `title` v = `{CARRNAME}`
)->a( n = `description` v = `{CARRID}`
)->a( n = `type` v = `Active`
)->a( n = `press` v = client->_event(
val = `PICK`
t_arg = VALUE #( ( `${CARRID}` ) ) ) ).
)->a( n = `press` v = client->_event( val = `PICK` arg = `${CARRID}` ) ).

client->popup_display( popup->stringify( ) ).

Expand Down
3 changes: 1 addition & 2 deletions docs/index.md
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Expand Up @@ -293,8 +293,7 @@ CLASS zcl_app_invoices IMPLEMENTATION.
)->tag( `Button`
)->a( n = `icon` v = `sap-icon://edit`
)->a( n = `tooltip` v = `Edit delivery date`
)->a( n = `press` v = client->_event( val = `EDIT`
t_arg = VALUE #( ( `${PRODUCT}` ) ) ) ).
)->a( n = `press` v = client->_event( val = `EDIT` arg = `${PRODUCT}` ) ).

client->view_display( view->stringify( ) ).

Expand Down
5 changes: 2 additions & 3 deletions docs/tutorials/walkthrough/step-10.md
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Expand Up @@ -76,7 +76,7 @@ CLASS zcl_app_walkthrough IMPLEMENTATION.
METHOD on_event.

" get_event( ) holds the name passed to _event( );
" get_event_arg( ) returns the extra argument attached via t_arg
" get_event_arg( ) returns the extra argument attached via arg
CASE client->get_event( ).
WHEN `READ`.
data_read( ).
Expand Down Expand Up @@ -177,8 +177,7 @@ CLASS zcl_app_walkthrough IMPLEMENTATION.
)->tag( `Button`
)->a( n = `icon` v = `sap-icon://edit`
)->a( n = `tooltip` v = `Edit delivery date`
)->a( n = `press` v = client->_event( val = `EDIT`
t_arg = VALUE #( ( `${PRODUCT}` ) ) ) ).
)->a( n = `press` v = client->_event( val = `EDIT` arg = `${PRODUCT}` ) ).

client->view_display( view->stringify( ) ).

Expand Down
5 changes: 2 additions & 3 deletions docs/tutorials/walkthrough/step-12.md
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Expand Up @@ -72,7 +72,7 @@ CLASS zcl_app_walkthrough IMPLEMENTATION.
METHOD on_event.

" get_event( ) holds the name passed to _event( );
" get_event_arg( ) returns the extra argument attached via t_arg
" get_event_arg( ) returns the extra argument attached via arg
CASE client->get_event( ).
WHEN `READ`.
data_read( ).
Expand Down Expand Up @@ -173,8 +173,7 @@ CLASS zcl_app_walkthrough IMPLEMENTATION.
)->tag( `Button`
)->a( n = `icon` v = `sap-icon://edit`
)->a( n = `tooltip` v = `Edit delivery date`
)->a( n = `press` v = client->_event( val = `EDIT`
t_arg = VALUE #( ( `${PRODUCT}` ) ) ) ).
)->a( n = `press` v = client->_event( val = `EDIT` arg = `${PRODUCT}` ) ).

client->view_display( view->stringify( ) ).

Expand Down
15 changes: 8 additions & 7 deletions docs/tutorials/walkthrough/step-6.md
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Expand Up @@ -59,8 +59,7 @@ CLASS zcl_app_walkthrough IMPLEMENTATION.
)->a( n = `description` v = `{SUPPLIER}`
)->a( n = `info` v = `{QUANTITY}`
)->a( n = `type` v = `Active`
)->a( n = `press` v = client->_event( val = `SHOW_INVOICE`
t_arg = VALUE #( ( `${PRODUCT}` ) ) ) ).
)->a( n = `press` v = client->_event( val = `SHOW_INVOICE` arg = `${PRODUCT}` ) ).

client->view_display( view->stringify( ) ).

Expand All @@ -80,11 +79,13 @@ ENDCLASS.
- **`type = Active`** makes the whole row clickable and gives it press
feedback; the `press` handler sits on the row template, so every row fires
the same event.
- **The argument rides with the event:**
``t_arg = VALUE #( ( `${PRODUCT}` ) )``. The `${...}` syntax is resolved
*per row* in the browser — each clone of the template carries its own
product name. On the server, `client->get_event_arg( )` returns it, and a
table read finds the row.
- **The argument rides with the event:** ``arg = `${PRODUCT}` ``. The
`${...}` syntax is resolved *per row* in the browser — each clone of the
template carries its own product name. On the server,
`client->get_event_arg( )` returns it, and a table read finds the row.
`arg` is the one-value spelling of `t_arg`: it is exactly
``t_arg = VALUE #( ( `${PRODUCT}` ) )``, and from two values on `t_arg` is
the parameter to use.
- **The state is still there.** `t_invoices` was filled in the
`check_on_navigated` branch of an earlier roundtrip — the framework
restored it before this one, so the event handler can read it. That is the
Expand Down
3 changes: 1 addition & 2 deletions docs/tutorials/walkthrough/step-7.md
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Expand Up @@ -61,8 +61,7 @@ CLASS zcl_app_walkthrough IMPLEMENTATION.
)->a( n = `description` v = `{SUPPLIER}`
)->a( n = `info` v = `{QUANTITY}`
)->a( n = `type` v = `Active`
)->a( n = `press` v = client->_event( val = `EDIT`
t_arg = VALUE #( ( `${PRODUCT}` ) ) ) ).
)->a( n = `press` v = client->_event( val = `EDIT` arg = `${PRODUCT}` ) ).

client->view_display( view->stringify( ) ).

Expand Down
3 changes: 1 addition & 2 deletions docs/tutorials/walkthrough/step-9.md
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Expand Up @@ -96,8 +96,7 @@ CLASS zcl_app_walkthrough IMPLEMENTATION.
)->tag( `Button`
)->a( n = `icon` v = `sap-icon://edit`
)->a( n = `tooltip` v = `Edit delivery date`
)->a( n = `press` v = client->_event( val = `EDIT`
t_arg = VALUE #( ( `${PRODUCT}` ) ) ) ).
)->a( n = `press` v = client->_event( val = `EDIT` arg = `${PRODUCT}` ) ).

client->view_display( view->stringify( ) ).

Expand Down
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