Hi ,
When I use RequestVar get the message: RequestVar ....... was set but not
read
My code like this:
object MyMgr {
...
Loc.Snippet("myFoo",myFoo)
...
object myId extends RequestVar[Long](0)
def myFoo(xhtml: NodeSeq): NodeSeq = {
....
def selectNode = {
myId .set(vId)
}
....
bind("",xhtml,
"node"->a(() => selectNode, Text(nodeName))
)
}
}
the RequestVar must be used at Class?
On Sat, Nov 21, 2009 at 12:09 AM, Ross Mellgren <dri...@gmail.com> wrote:
> RequestVar is the standard way of doing this. For example
>
> object MySharedInformation {
> object myData extends RequestVar[List[Thing]](loadThings)
> // ^^^^^^^^^^^ ^^^^^^^^^^
> // Type of thing to store How to initialize
> variable first time it's accessed
>
> private def loadThings: List[Thing] = ...
> }
>
> class Snippet1 {
> import MySharedInformation.myData
> def render(ns: NodeSeq): NodeSeq = {
> myData.is.map(thing => { ... })
> }
> }
>
> class Snippet2 {
> import MySharedInformation.myData
> ...
> }
>
> The lifetime of the value is during the current request processing and
> any AJAX calls related to it.
>
> If you really want to initialize it in a snippet, then use a Box with
> a RequestVar, like this:
>
> object MySharedInformation {
> object myData extends RequestVar[Box[List[Thing]]](Empty)
> }
>
> class LoaderSnippet {
> import MySharedInformation.myData
> def render(ns: NodeSeq): NodeSeq = {
> myData.set(Full(...))
> }
> }
>
> class ReaderSnippet {
> import MySharedInformation.myData
> def render(ns: NodeSeq): NodeSeq = {
> // If the data has not been loaded, default to an empty list
> val data = myData.is.openOr(Nil)
> ...
> }
> }
>
> class OtherReaderSnippet {
> import MySharedInformation.myData
> def render(ns: NodeSeq): NodeSeq = {
> // Do two entirely different things if the data has versus
> has not been loaded
> myData.is match {
> case Full(data) => // do something when the data has been
> loaded
> case _ => // do something when the data has not been loaded
> }
> }
> }
>
> HTH,
> -Ross
>
>
> On Nov 20, 2009, at 10:59 AM, Alex Black wrote:
>
> > I've got a template page, say foobar.html, that makes a number of
> > calls to functions in a snippet, e.g. mysnippet.foo1, mysnippet.foo2,
> > mysnippet.foo3.
> >
> > I'd like to do some initial work in foo1, e.g. retrieve some data and
> > do some work on it, then in foo2 and foo3 display parts of that data.
> >
> > Whats the easiest way to do this? I think I misunderstood the lift
> > book:
> >
> > "That means that for each request, Lift creates a new instance of the
> > snippet class to execute. Any changes you make to instance variables
> > will be discarded after the request is processed."
> >
> > I thought this meant that for a given HTTP request, there would be one
> > (and only one) instance of my snippet, so I could call several of its
> > methods and they could all access the snippet's member variables,
> > which would then be discarded at the end of the request.
> >
> > Am I going about this wrong? should I only have one snippet function
> > per template?
> >
> > Thx
> >
> > - Alex
> >
> > --
> >
> > You received this message because you are subscribed to the Google
> > Groups "Lift" group.
> > To post to this group, send email to lift...@googlegroups.com.
> > To unsubscribe from this group, send email to
> liftweb+unsubscr...@googlegroups.com<liftweb%2bunsubscr...@googlegroups.com>
> > .
> > For more options, visit this group at
> http://groups.google.com/group/liftweb?hl=
> > .
> >
> >
>
> --
>
> You received this message because you are subscribed to the Google Groups
> "Lift" group.
> To post to this group, send email to lift...@googlegroups.com.
> To unsubscribe from this group, send email to
> liftweb+unsubscr...@googlegroups.com<liftweb%2bunsubscr...@googlegroups.com>
> .
> For more options, visit this group at
> http://groups.google.com/group/liftweb?hl=.
>
>
>
--
Scala中文社区: http://groups.google.com/group/scalacn
--
You received this message because you are subscribed to the Google Groups
"Lift" group.
To post to this group, send email to lift...@googlegroups.com.
To unsubscribe from this group, send email to
liftweb+unsubscr...@googlegroups.com.
For more options, visit this group at
http://groups.google.com/group/liftweb?hl=en.
