This
This -> Function result
| Parameter | Type | Description | |
|---|---|---|---|
| Function result | Object | 🡐 | Current element or object |
Description
The This command returns a reference to the currently processed object.
The command is designed to be used in the following contexts:
- A list box associated to a collection or an entity selection, during the On Display Detail or the On Data Change events.
In this context, the command returns a reference to the collection element or entity accessed by the list box to display the current row.
Note: If you use a collection of scalar values in a list box, 4D creates an object for each element with a single value property. Thus, the element value is returned by the This.value non-assignable expression. - The execution of a formula object created by the Formula or Formula from string commands.
In this context, the command returns a reference to the object currently processed by the formula.
In any other context, the command returns Null.
Within supported contexts, you will access object/collection element properties or entity attributes through This.<propertyPath>. For example, This.name or This.employer.lastName are valid pathes to object, element or entity properties.
Example 1
{
"ID": 1234
"name": "Xavier",
"revenues": 47300,
"employees": [
"Allan",
"Bob",
"Charlie"
]
},{
"ID": 2563
"name": "Carla",
"revenues": 55000,
"isFemale": true
"employees": [
"Igor",
"Jane"
]
},...
Example 2
You want to display entities from the following structure in a list box:
You build a list box of the "Collection or entity selection" type with the following definition:
Note that:
- This.ID, This.Title and This.Date directly refers to the corresponding attributes in the ds.Event dataclass.
- This.meetings is a related attribute (based upon the One To Many relation name) that returns an entity selection of the ds.Meeting dataclass.
- Form.eventList is the entity selection that is attached to the list box. The initialization code can be put in the on load form event:
Case of
:(Form event code=On Load)
Form.eventList:=ds.Event.all() //returns an entity selection with all entities
End case
Once the form is executed, the list box is automatically filled with the entity selection:
Example 3
You want to use a project method as a formula encapsulated in an object:
var $person : Object
$person:=New object
$person.firstName:="John"
$person.lastName:="Smith"
$person.greeting:=Formula(Greeting)
$g:=$person.greeting("hello") // returns "hello John Smith"
$g:=$person.greeting("hi") // returns "hi John Smith"
With the Greeting project method:
var $0;$1 : Text
$0:=$1+" "+This.firstName+" "+This.lastName