Flex 4 数据绑定

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1 Object和ObjectProxy在Binding时的区别

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[Bindable]public var userObject:Object=new Object();[Bindable]public var userProxy:ObjectProxy=new ObjectProxy();

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<mx:FormItem label="Object">     <s:TextInput text="@{userObject.name}"/></mx:FormItem><mx:FormItem label="ObjectProxy">     <s:TextInput text="@{userProxy.name}"/></mx:FormItem>

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会产生运行时warning

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package org.swflash.model{ public class Account { public function Account(name:String) { this.name = name; } public var name:String; }}?

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[Bindable]public var account:Account = new Account();<mx:FormItem label="Account">      <s:TextInput text="@{account.name}"/></mx:FormItem>

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?在项目编译时报下面警告：

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[Bindable]public class Account{ ...}?

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如果取消[Bindable]public var account:Account = new Account();前面的[Bindable]标签，则会产生如下的编译时warning

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[Bindable]public var userObject:Object={"name":"swflash"};[Bindable]public var userProxy:ObjectProxy=new ObjectProxy({"name":"swflash"});[Bindable]public var account:Account = new Account("swflash");?

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1)双向绑定代码如下：

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private function userBidirectionalBinding():void{{    trace("Object.name:"+userObject.name);    trace("ObjectProxy.name:"+userProxy.name);    trace("Account.name:"+account.name);}

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更改输入的值为swf后，控制台输出如下：

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private function userBinding():void{ trace("Object.name:"+userObject.name); trace("ObjectProxy.name:"+userProxy.name); trace("Account.name:"+account.name); userObject.name = objNameInput.text; proxyNameInput.name = proxyNameInput.text; account.name = accountNameInput.text; trace("Object.name:"+userObject.name); trace("ObjectProxy.name:"+userProxy.name); trace("Account.name:"+account.name);}?

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注意，需要取消text="@{account.name}"中的@

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更改输入的值为swflasha后，控制台输出如下：

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?写道Object.name:swflasha
ObjectProxy.name:swflash
Account.name:swflasha
Object.name:swflasha
ObjectProxy.name:swflash
Account.name:swflasha?

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可见单向绑定在UI更改的情况下，ObjectProxy的数据感应不到更改。

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小结：使用双向绑定简洁可靠，推荐使用。

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