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() : 4D.Class .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
Description
The .name property contains the name of the 4D.Class object. Class names are case sensitive.
This property is read-only.
.new()
History
| Version | Changes |
|---|---|
| v18 R3 | Added |
.new() : 4D.Class
.new( param : any { ;...paramN } ) : 4D.Class
| Parameter | Type | Description | |
|---|---|---|---|
| param | any | -> | Parameter(s) to pass to the constructor function |
| Result | 4D.Class | <- | New object of the class |
Description
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.
Examples
To create a new instance of the Person class:
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
Description
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.
Examples
$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