Macromedia flex builder-using flex builder 用户手册

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Chapter 5:  Working with Components

To specify component namespaces in your code:

•

Depending on the type and location of the component you want to insert, specify the 
namespace as follows:

Standard Macromedia controls and containers 

If working with a standard Macromedia 

control or container, you don’t need to specify a namespace. The namespace for all 
Macromedia components is http://www.macromedia.com/2003/mxml/ and is specified in the 

<mx:Application>

 tag.

For example, if you want to insert a ComboBox control, which is a Macromedia component, 
enter the ComboBox tag between the opening and closing 

<mx:Application>

 tags, as follows:

<mx:Application xmlns:mx="http://www.macromedia.com/2003/mxml">

<mx:ComboBox/>

</mx:Application>

You can omit the 

mx

 prefix from the component tag if you don’t specify it in the 

xmlns

 

property name (you use 

xmlns="..."

 instead of 

xmlns:mx="..."

). The following example is 

identical to the previous one, except that the prefix is omitted from the component tag:

<Application xmlns="http://www.macromedia.com/2003/mxml">

<ComboBox/>

<Application>

Custom MXML and ActionScript components

  If you want to insert a custom MXML or 

ActionScript component, the namespace is defined by the location of the component file in 
the application’s root folder on the server.

For example, if you write a custom MXML component called myButton.mxml and save it on 
the Flex server in the assets/components/mycontrols subfolder in your application root folder, 
enter the following namespace for the component:

xmlns:xyz="assets.components.mycontrols.*"

The property suffix 

:xyz

 tells you what tag prefix to use to reference the components in the 

specified namespace. If the suffix is 

:xyz

, then use the 

xyz:

 tag prefix in your code to reference 

a component in the namespace, as follows:

<xyz:myButton xmlns:xyz="assets.components.mycontrols.*" />

If the component file is located in the application root folder itself, the namespace is * 
(asterisk), as follows: 

... xmlns:xyz="*"

The namespace is also * (asterisk) if the component file is located in the /WEB-INF/flex/
user_classes subfolder in your application’s root folder on the server. For example, if you place 
the myButton.mxml component file in the /WEB-INF/flex/user_classes folder on the server, 
enter the following tag to insert the component into an MXML file:

<xyz:myButton xmlns:xyz="*" />

Note: If two components have the same name and one is located in the application root folder and 
the other is located in the WEB-INF folder, the component in the application root folder is used 
first.