Speaking about Communicating between Components. In reality
everything is custom, specifically custom renderers. What I have been
having problem with is to how to populate properties of a custom
component and how to execute its methods before the component is
added to a parent container, another words before this:
Column.itemRenderer = customRenderer;
--- In flexcoders@yahoogroups.com, "Tracy Spratt" <[EMAIL PROTECTED]> wrote:
>
> There are many ways. Below is a document I started, but have not
> polished, but should be of some use.
>
> Tracy
>
>
>
> Communicating between Components:
>
>
>
> Note: for "loose coupling" use events. But that is another topic.
>
>
>
> A non-trivial flex application is "component" based. While all of
the
> built-in controls are components, the question of communicating
between
> components most often arises when you are using a custom component.
A
> custom component, whether implemented in mxml or ActionScript, has
its
> own "scope". Within that component (Application is a component
too!),
> all sibling child controls share the same scope, so you can refer to
> controls by their id. If the controls(components) have public
> properties or methods, you can reference those members directly
through
> the id:
>
> <mx:TextInput id="textinput1" text="test value" .../>
>
> <mx:Text id="text1" ... text="{textinput1.text}" .../>
>
>
>
> Ok, so far, its a "duh" right?
>
>
>
> When you use custom components in a Flex app, at run time they make
a
> document object model hierarchy (DOM). Each subcomponent has its
own
> scope and code within that component can't *directly* reference the
> member properties or methods of its sibling subcomponents.
>
>
>
> So again, within a component, code can reference children
directly, as
> in the example above. But there are two other cases inherent in a
> hierarchy. You might want to reference "up", to get to public
members
> of the parent, grandparent, etc, or 'down", to get to
a "grandchild".
>
>
>
> Accessing members in the parent:
>
> On an ordinary component DOM, you can reference the parent component
> using the .parent property. Say that a control with id="textinput1"
> exists in the parent of the current component. then you could do:
>
> <mx:Text id="text1" ... text="{parent.textinput1.text}"
> .../>
>
>
>
> Accessing members in the main application:
>
> Components can be nested, sometimes very deeply. If the reference
you
> want is all the way at the top-level, main application (the one
with the
> <mx:Application> tag), you could do
> {parent.parent.parent.textinput1.text}, but you would have to count
the
> component levels just right. Instead, you can use
> Application.application to get to that scope:
>
> <mx:Text id="text1" ...
> text="{Application.application.textinput1.text}" .../>
>
> You can shoretn this style of reference by importing
> mx.core.Application, and assigning Application.application to a
> variable, like _app, the doing (_app.textinput1.text)
>
>
>
> Accessing components of a child component ("grandchildren"):
>
> Say that in this case, a child component has the TextInput control
you
> want to reference. First, make sure the child component has an id:
>
> <myComp:MyCustomComp id="mycc1" .../>
>
> Then, in the same scope (the same component/file that
contains "mycc1"
> above) you can say:
>
> <mx:Text id="text1" ...
text="{mycc1.textinput1.text}" .../>
>
>
>
> Accessing a nested component:
>
> As mentioned above you can go "up" the hierarchy using
> "parent.parent...". You can also go "down" the hirearchy using id
> references:
>
> <mx:Text id="text1" ...
> text="{mycc1.mycc11.mycc.12.textinput1.text}" .../>
>
>
>
> Additional notes:
>
> If you are using SWFLoader to load an entire Application, you can
> reference the immediate parent application using "parentDocument".
You
> can also use Application.application to reach the main app, as shown
> above.
>
>
>
> Accessing members of an application loaded by SWFLoader is a bit
more
> complicated. See the example here:
>
> http://www.cflex.net/showFileDetails.cfm?ObjectID=690
>
>
>
>
>
> ________________________________
>
> From: flexcoders@yahoogroups.com
[mailto:[EMAIL PROTECTED] On
> Behalf Of Luke Vanderfluit
> Sent: Tuesday, April 22, 2008 7:08 PM
> To: flexcoders@yahoogroups.com
> Subject: [flexcoders] passing parameters to components
>
>
>
> Hi.
>
> I have a flex application that gets called from an html link and is
> passed a
> parameter. The param is personid.
>
> I retrieve the parameter in the flex application (BrowserManager).
> So I have access to it in the main application file.
>
> I have a number of components within the main application, that do
> server
> requests. In some of those requests I need to pass the personid
(that I
> have
> retrieved from the browser url).
>
> My question is:
>
> What is the accepted method of passing variables (params) between
> components,
> specifically, in this case, from parent to child component?
>
> Thanks for your responses.
>
> Kind regards.
> Luke.
>
> --
> Luke Vanderfluit
> Analyst / Web Programmer
> e3Learning.com.au
> 08 8221 6422
>
