Re: Pass-through bindings from parent to child component
Re: Pass-through bindings from parent to child component
- Subject: Re: Pass-through bindings from parent to child component
- From: Paul Hoadley <email@hidden>
- Date: Mon, 7 Jan 2008 16:55:10 +1030
Hi Chuck,
On 07/01/2008, at 3:27 PM, Chuck Hill wrote:
On 03/01/2008, at 4:18 PM, Paul Hoadley wrote:
Is there an idiom for passing through _any and all_ bindings from
a parent to a child component without being specific about it?
Simply put, no. The is reason is that parents do not pass bindings
to their children. The children take them from their parents. If
the child was not written to handle arbitrary bindings, there is no
way you can force it to. You could subclass the child and extend it
to handle any and all bindings.
OK, there's something important I was missing.
That is, I've got a component that wraps a Dynamic Element. If I
add the binding 'abc="xyz"' to, say, a WOTextField, it will pass
that through to the HTML 'input' element as an attribute and its
value.
It does not pass them through to WOTextField. WOTextField (or one
of its superclasses, WOInput or WOHTMLElement, I don't recall and am
too lazy to figure it out) has code to take any bindings that it
does not recognize and add them to the input as key=value.
OK.
How can I get my containing component to do something similar—is
there an idiom for passing completely arbitrary bindings from a
parent to a child component? If I can work that out, I think I can
answer my original questions:
1. I want to be able to set any bindings on the WOBrowser which
were set on the LSBrowser. I can list them out in the WOD:
browser : WOBrowser {
list = ^list;
item = ^item;
selections = ^selections;
displayString = ^displayString;
multiple = ^multiple;
id = ^id;
value = ^value;
escapeHTML = ^escapeHTML;
selectedValues = ^selectedValues;
name = ^name;
disabled = ^disabled;
size = ^size;
class = classList;
}
But then WOLips flags an error because I've "set" 'selectedValues'
and 'selections'. All I'm trying to express here is that
whichever of the two is set on the parent should be passed through
to the child.
I think that what you need to do is to implement LSBrowser as a
WODynamicElement so that you have the necessary access to the
bindings. This means that instead of using a WOBrowser, you are
going to have to re-implement it. Subclassing WOBrowser might be a
good approach.
Maybe I've wandered too far down the wrong path here, so I'll ask a
different question. For now, the only additional functionality I'm
trying to add to the dynamic elements is the classList() method
referred to in the WOD above. (This returns a string containing a
space-separated list of classes which ends up as the value of the HTML
"class" attribute for CSS styling.) So I've created an LSComponent
which extends WOComponent and implements classList(). So currently
LSBrowser extends LSComponent. If I have LSBrowser extend WOBrowser
(or WODynamicElement), I'm going to need to duplicate classList() in
LSTextField, LSCheckBox, and so on. Am I going about this (adding a
method to the standard dynamic elements) the wrong way?
--
Paul.
w http://logicsquad.net/
h http://paul.hoadley.name/
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