Gambas/syntax/variables/classes/inheritance - Revision history

Woozle: another inheritance issue

2015-05-16T20:37:15Z

another inheritance issue

← Older revision		Revision as of 20:37, 16 May 2015
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	* To call the ancestor's version of a method, refer to the parent as "[http://gambaswiki.org/wiki/lang/super Super]".		* To call the ancestor's version of a method, refer to the parent as "[http://gambaswiki.org/wiki/lang/super Super]".
	* If ClassB inherits from ClassA, and ObjectB is declared as ClassA, it will use ClassA's methods even if it receives an object of ClassB. To make use of virtual methods (in this case, methods in ClassB), declare ObjectB as a "Variant" instead of "ClassA".		* If ClassB inherits from ClassA, and ObjectB is declared as ClassA, it will use ClassA's methods even if it receives an object of ClassB. To make use of virtual methods (in this case, methods in ClassB), declare ObjectB as a "Variant" instead of "ClassA".
			* If ClassB inherits methods from ClassA, and ObjectB is declared as ClassB, and ObjectB is asked to execute a method that is defined only in ClassA, and that method calls another method that is defined in both ClassA and ClassB, it will apparently call the ClassA method unless invoked as "Me.method". (This needs to be verified... because how would you then call a private method?)
	==Documentation==		==Documentation==
	To specify that your class should inherit from the <u>ParentClass</u> class, insert at the beginning of the class file:<gambas>INHERITS ParentClass</gambas>		To specify that your class should inherit from the <u>ParentClass</u> class, insert at the beginning of the class file:<gambas>INHERITS ParentClass</gambas>

Woozle: inheritance and virtual methods

2015-05-13T20:21:06Z

inheritance and virtual methods

← Older revision		Revision as of 20:21, 13 May 2015
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	==Notes==		==Notes==
	To call the ancestor's version of a method, refer to the parent as "[http://gambaswiki.org/wiki/lang/super Super]".		* To call the ancestor's version of a method, refer to the parent as "[http://gambaswiki.org/wiki/lang/super Super]".
			* If ClassB inherits from ClassA, and ObjectB is declared as ClassA, it will use ClassA's methods even if it receives an object of ClassB. To make use of virtual methods (in this case, methods in ClassB), declare ObjectB as a "Variant" instead of "ClassA".
	==Documentation==		==Documentation==
	To specify that your class should inherit from the <u>ParentClass</u> class, insert at the beginning of the class file:<gambas>INHERITS ParentClass</gambas>		To specify that your class should inherit from the <u>ParentClass</u> class, insert at the beginning of the class file:<gambas>INHERITS ParentClass</gambas>

Woozle: note about "Super"; moved acknowledgements template to bottom

2015-04-26T22:48:50Z

note about "Super"; moved acknowledgements template to bottom

← Older revision		Revision as of 22:48, 26 April 2015
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			==Notes==
			To call the ancestor's version of a method, refer to the parent as "[http://gambaswiki.org/wiki/lang/super Super]".
	==Documentation==		==Documentation==
	~~{{gambasF1\|1.0.13}}~~		To specify that your class should inherit from the <u>ParentClass</u> class, insert at the beginning of the class file:<gambas>INHERITS ParentClass</gambas>
	To specify that your class should inherit from the <u>ParentClass</u> class, insert ~~this~~ at the beginning of the class file:		Note that if you are inheriting from a {{l/same\|virtual}} class, you need to leave off the period (e.g. to inherit from '''.ListViewItem''', use "INHERITS ListViewItem").
	~~INHERITS~~ <u>ParentClass</u>
	Note that if you are inheriting from a ~~[[virtual class (Gambas)~~\|virtual class]], you need to leave off the period (e.g. to inherit from '''.ListViewItem''', use "INHERITS ListViewItem").
	===What is inherited?===		===What is inherited?===
	The class inherits from its parent every method, property, constant and event.		The class inherits from its parent every method, property, constant and event.
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	==Errors==		==Errors==
	* "[[Bad use of virtual class (Gambas)\|Bad use of virtual class]]"		* "[[Bad use of virtual class (Gambas)\|Bad use of virtual class]]"
			==Acknowledgements==
			{{gambasF1\|1.0.13}}

Woozle: Woozle moved page Gambas/inheritance to Gambas/syntax/variables/classes/inheritance: reorganizing

2015-04-25T18:30:53Z

Woozle moved page Gambas/inheritance to Gambas/syntax/variables/classes/inheritance: reorganizing

← Older revision	Revision as of 18:30, 25 April 2015
(No difference)

Woozle: post-move tidying

2013-04-28T15:25:10Z

post-move tidying

← Older revision		Revision as of 15:25, 28 April 2013
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	~~==Navigation==~~
	~~[[computing]]: [[software]]: [[programming]]: [[Gambas]]: [[inheritance (Gambas)\|inheritance]]~~
	==Documentation==		==Documentation==
	{{gambasF1\|1.0.13}}		{{gambasF1\|1.0.13}}

Woozle: Woozle moved page inheritance (Gambas) to Gambas/inheritance: reorganizing

2013-04-28T15:23:55Z

Woozle moved page inheritance (Gambas) to Gambas/inheritance: reorganizing

← Older revision	Revision as of 15:23, 28 April 2013
(No difference)

Woozle: /* Inheritance and constructor */ errors: bad use of vclass

2006-11-19T02:13:15Z

Inheritance and constructor: errors: bad use of vclass

← Older revision		Revision as of 02:13, 19 November 2006
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	You then create a MyListBox control this way:		You then create a MyListBox control this way:
	* aMyListBox = NEW MyListBox ( "Name", aContainer )		* aMyListBox = NEW MyListBox ( "Name", aContainer )
			==Errors==
			* "[[Bad use of virtual class (Gambas)\|Bad use of virtual class]]"

Woozle: /* Documentation */ inheriting from virtual classes

2006-11-19T00:51:42Z

Documentation: inheriting from virtual classes

← Older revision		Revision as of 00:51, 19 November 2006
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	To specify that your class should inherit from the <u>ParentClass</u> class, insert this at the beginning of the class file:		To specify that your class should inherit from the <u>ParentClass</u> class, insert this at the beginning of the class file:
	INHERITS <u>ParentClass</u>		INHERITS <u>ParentClass</u>
			Note that if you are inheriting from a [[virtual class (Gambas)\|virtual class]], you need to leave off the period (e.g. to inherit from '''.ListViewItem''', use "INHERITS ListViewItem").
	===What is inherited?===		===What is inherited?===
	The class inherits from its parent every method, property, constant and event.		The class inherits from its parent every method, property, constant and event.

Woozle at 00:49, 19 November 2006

2006-11-19T00:49:18Z

New page

==Navigation==
[[computing]]: [[software]]: [[programming]]: [[Gambas]]: [[inheritance (Gambas)|inheritance]]
==Documentation==
{{gambasF1|1.0.13}}
To specify that your class should inherit from the <u>ParentClass</u> class, insert this at the beginning of the class file:
INHERITS <u>ParentClass</u>
===What is inherited?===
The class inherits from its parent every method, property, constant and event.
===Which class can be a parent class?===
You can inherit any class, even a native one!

For example, you can create a custom MyListBox class that inherits ListBox but allows association a tag with each list item.

Note that you can't use INHERITS in a form class file, because forms already inherits the Form class.
===Inheritance and constructor===
Unlike many (or most) object-oriented languages, in Gambas each class in the inheritance hierarchy consumes the parameters passed to the constructor.

Let's suppose we have the following inheritance tree:
* MyListBox ---inherits--> ListBox ---inherits---> Control
** '''Control._new'''() does not exist.
** '''ListBox._new'''() takes one parameter: the parent control.
** '''MyListBox._new'''() takes one parameter: a name - It is just an example.
So NEW '''MyListBox'''() will take two parameters. The first will be sent to '''MyListBox._new'''(), the second to '''ListBox._new'''(). But the '''ListBox._new'''() will be called first. This way, you are sure that the ListBox control exists when you are in '''MyListBox._new'''().

You then create a MyListBox control this way:
* aMyListBox = NEW MyListBox ( "Name", aContainer )