@init"

From Documentation
m ((via JWB))
 
(8 intermediate revisions by 2 users not shown)
Line 1: Line 1:
 
{{ZKDevelopersReferencePageHeader}}
 
{{ZKDevelopersReferencePageHeader}}
 +
{{Deprecated | url=[http://books.zkoss.org/zk-mvvm-book/8.0/syntax/databindinginit.html zk-mvvm-book/8.0/syntax/data_binding/init]|}}
  
  
 
=Syntax=
 
=Syntax=
  
−
<tt> @init(</tt>  ''[EvaluateOnce EL-expression], [arbitraryKey]=[EL-expression] '' <tt>) </tt>
+
<code>@init(</code>  ''[EvaluateOnce EL-expression], [arbitraryKey]=[EL-expression] '' <code>)</code>
  
 
= Description =
 
= Description =
Line 11: Line 12:
 
'''Purpose:''' Initialize an attribute's value and no reload during user interaction.
 
'''Purpose:''' Initialize an attribute's value and no reload during user interaction.
  
−
The EL expression in this annotation is only evaluated once when binder parses it. When you use it in "viewModel" attribute, binder will try to resolve the EL expression as a class and create an instance of it.  
+
The EL expression in this annotation is only evaluated once when binder parses it. When you use it on "viewModel" attribute, binder will try to resolve the EL expression as a class and create an instance of it.  
  
 
In "form" attribute, the result of evaluating the EL expression should be a <javadoc> org.zkoss.bind.Form</javadoc> object.  
 
In "form" attribute, the result of evaluating the EL expression should be a <javadoc> org.zkoss.bind.Form</javadoc> object.  
  
 
For other attributes, binder initializes their value with EL evaluation result.
 
For other attributes, binder initializes their value with EL evaluation result.
 +
 +
When using on "viewModel" attribute, we can pass arguments in key-value pairs with comma separated. And we can get the arguments in a initial method of ViewModel by <code>[[ZK_Developer%27s_Reference/MVVM/Syntax/ViewModel/Parameters/@BindingParam| @BindingParam]]</code>.
 +
 +
;''[arbitraryKey]=[EL-expression]''
 +
: It's key-value pairs basically. You can write multiple key-value pairs with different key names.
 +
: An EL expression without key is set to a default key named '''"value"''' implicitly.
 +
: Due to each annotation has different functions, some annotations may ignore key-value pair expression other than default key, e.g.@id.
 +
 +
;''[arbitraryKey]''
 +
: It could be any name, it's used as a key for parameter related Java annotation in a ViewModel.
  
 
= Example =
 
= Example =
Line 33: Line 44:
 
</vbox>
 
</vbox>
  
 +
</source>
 +
 +
 +
'''Pass arguments'''
 +
<source lang="xml" highlight='2'>
 +
<window  width="400px" apply="org.zkoss.bind.BindComposer"
 +
viewModel="@id('vm') @init('org.zkoss.reference.developer.mvvm.databinding.InitVM', arg1='myValue')">
 +
...
 +
</window>
 +
</source>
 +
 +
<source lang="java" highlight='4'>
 +
public class InitVM {
 +
 +
@Init
 +
public void init(@BindingParam("arg1") String arg1){
 +
System.out.println("arg1: "+arg1);
 +
}
 +
}
 
</source>
 
</source>
  
 
=Version History=
 
=Version History=
−
{{LastUpdated}}
+
 
−
{| border='1px' | width="100%"
+
{| class='wikitable' | width="100%"
 
! Version !! Date !! Content
 
! Version !! Date !! Content
 
|-
 
|-

Latest revision as of 07:35, 8 July 2022


DocumentationZK Developer's ReferenceMVVMSyntaxData Binding@init
@init


Stop.png This article is out of date, please refer to zk-mvvm-book/8.0/syntax/data_binding/init for more up to date information.


Syntax

@init( [EvaluateOnce EL-expression], [arbitraryKey]=[EL-expression] )

Description

Target Attribute: any

Purpose: Initialize an attribute's value and no reload during user interaction.

The EL expression in this annotation is only evaluated once when binder parses it. When you use it on "viewModel" attribute, binder will try to resolve the EL expression as a class and create an instance of it.

In "form" attribute, the result of evaluating the EL expression should be a Form object.

For other attributes, binder initializes their value with EL evaluation result.

When using on "viewModel" attribute, we can pass arguments in key-value pairs with comma separated. And we can get the arguments in a initial method of ViewModel by @BindingParam.

[arbitraryKey]=[EL-expression]
It's key-value pairs basically. You can write multiple key-value pairs with different key names.
An EL expression without key is set to a default key named "value" implicitly.
Due to each annotation has different functions, some annotations may ignore key-value pair expression other than default key, e.g.@id.
[arbitraryKey]
It could be any name, it's used as a key for parameter related Java annotation in a ViewModel.

Example

Usage example in viewModel attribute 

<window apply="org.zkoss.bind.BindComposer" viewModel="@id('vm') @init('foo.ChildrenMenuVM')" >
</window>


Usage example in form attribute 

<vbox form="@id('fx') @init(vm.myForm) @load(vm.person) @save(vm.person, before='save')">
</vbox>


Pass arguments 

	<window  width="400px" apply="org.zkoss.bind.BindComposer"
	viewModel="@id('vm') @init('org.zkoss.reference.developer.mvvm.databinding.InitVM', arg1='myValue')">
		...
	</window>

public class InitVM {

	@Init
	public void init(@BindingParam("arg1") String arg1){
		System.out.println("arg1: "+arg1);
	}
}

Version History

Version Date Content
6.0.0 February 2012 The MVVM was introduced.




Last Update : 2022/07/08

Copyright © Potix Corporation. This article is licensed under GNU Free Documentation License.


Retrieved from "https://www.zkoss.org/_w/index.php?title=ZK_Developer%27s_Reference/MVVM/Syntax/Data_Binding/@init&oldid=54752"