[Seaside] Error: Components not found

Colin Putney cputney at wiresong.ca
Thu Oct 21 20:55:23 CEST 2004

Avi Bryant wrote:

> A component's callbacks are evaluated in the dynamic context of its 
> ancestors in the UI tree.  This lets its ancestors "control" those 
> callbacks - they can prevent them from executing if the user has not 
> been authenticated, for example, or they can catch validation errors 
> that occur within them and record these for displaying to the user 
> later, or they can set up thread-local variables that will be useful to 
> them, and so on.  To achieve this, the component tree is walked 
> recursively during callback processing, and the callbacks for each 
> component are executed as it is visited.  The #children method controls 
> this traversal - it's what's used to know which subcomponents to recurse 
> into.  If a component isn't listed in #children, it won't get visited, 
> and so its callbacks will never get executed.

You know, this is enough of a FAQ that it might be worthwhile to have 
the superclass implementation call #subclassResponsibility and have a 
comment similar to the above paragraph.

It might be a little annoying for components that don't have children, 
but at least it would be clear.


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