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Class

When a user class is defined in the project, it is loaded in the 4D language environment. A class is an object itself, of "Class" class, which has properties and a function.

Summary

.name : Text     contains the name of the 4D.Class object
.new( param : any { ;...paramN } ) : 4D.Class     creates and returns a cs.className object which is a new instance of the class on which it is called
.superclass : 4D.Class     returns the parent class of the class

.name

History

Version	Changes
v18 R3	Added

.name : Text

Beschreibung

The .name property contains the name of the 4D.Class object. Es wird zwischen Groß- und Kleinschreibung unterschieden.

This property is read-only.

.new()

History

Version	Changes
v18 R3	Added

.new( param : any { ;...paramN } ) : 4D.Class

Parameter	Typ		Beschreibung
param	any	->	Parameter(s) to pass to the constructor function
Ergebnis	4D.Class	<-	New object of the class

Beschreibung

The .new() function creates and returns a cs.className object which is a new instance of the class on which it is called. This function is automatically available on all classes from the cs class store.

You can pass one or more optional param parameters, which will be passed to the class constructor function (if any) in the className class definition. Within the constructor function, the This is bound to the new object being constructed.

If .new() is called on a non-existing class, an error is returned.

Beispiele

Eine neue Instanz der Klasse Person anlegen:

var $person : cs.Person  
$person:=cs.Person.new() //create the new instance  
//$person contains functions of the class

To create a new instance of the Person class with parameters:

//Class: Person.4dm
Class constructor($firstname : Text; $lastname : Text; $age : Integer)
    This.firstName:=$firstname
    This.lastName:=$lastname
    This.age:=$age

//In a method
var $person : cs.Person  
$person:=cs.Person.new("John";"Doe";40)  
//$person.firstName = "John"
//$person.lastName = "Doe"
//$person.age = 40

.superclass

History

Version	Changes
v18 R3	Added

.superclass : 4D.Class

Beschreibung

The .superclass property returns the parent class of the class. A superclass can be a 4D.Class object, or a cs.className object. If the class does not have a parent class, the property returns null.

A superclass of a user class is declared in a class by using the Class extends <superclass> keyword.

This property is read-only.

Beispiele

$sup:=4D.File.superclass //Document
$sup:=4D.Document.superclass //Object
$sup:=4D.Object.superclass //null

// If you created a MyFile class  
// with `Class extends File`
$sup:=cs.MyFile.superclass //File 

See also: Super