You are viewing a plain text version of this content. The canonical link for it is here.
Posted to users@wicket.apache.org by Arjun Dhar <dh...@yahoo.com> on 2011/01/15 08:07:29 UTC
Changing/Accessing name of ListItem in ListView
Hi,
when using a ListView, the name uses the following format to Render. <loop
name>:<index>:<field id>
In onSubmit(..); this is fine if you know the order of the list. However say
if the primary data Structure is a hashmap then its more convenient/elegant
to retrieve by Name. I can change the name of the attribute but Wicket does
not recognize it when one does get(<componentId>).
Using ListView.getList() I can access the Model, but this does not help
getting the access to the individual components.
Looks like the only way is to use a numberic counter and construct the
Component ID's to access it one my one.
Is there a way to change the component Id ..or perhaps access these by name?
--
View this message in context: http://apache-wicket.1842946.n4.nabble.com/Changing-Accessing-name-of-ListItem-in-ListView-tp3218777p3218777.html
Sent from the Users forum mailing list archive at Nabble.com.
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@wicket.apache.org
For additional commands, e-mail: users-help@wicket.apache.org
Re: Changing/Accessing name of ListItem in ListView
Posted by Arjun Dhar <dh...@yahoo.com>.
Your bet was right, it was onSubmit()! I understand better now.
On a funny note; I can imagine Igor exasperated "...This guys on a
different tangent..." :)
"Don't worry - it's probably the most common mistake Wicket newbs make!
It's
definitely the thing I stress understanding the most in my Wicket classes. "
.... thanks, honestly it comforting to know I'm not a complete moron :)
On a technical Note (further understanding):
I had read about "Bindgen" and it highlighted the issues with using
PropertyModels, and Bindgen is a bit more inconvenient. So I guess I
somewhere lost my track. Now I realize the pitfall of not following either.
...valuable lesson.
Thanks guys, very much appreciated!
--
View this message in context: http://apache-wicket.1842946.n4.nabble.com/Changing-Accessing-name-of-ListItem-in-ListView-tp3218777p3219725.html
Sent from the Users forum mailing list archive at Nabble.com.
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@wicket.apache.org
For additional commands, e-mail: users-help@wicket.apache.org
Re: Changing/Accessing name of ListItem in ListView
Posted by Jeremy Thomerson <je...@wickettraining.com>.
On Sat, Jan 15, 2011 at 9:34 PM, Jeremy Thomerson <jeremy@wickettraining.com
> wrote:
>
>
> On Sat, Jan 15, 2011 at 6:36 AM, Arjun Dhar <dh...@yahoo.com> wrote:
>
>>
>> I was hoping on the lines, where you do "get(<component id>)"; Wicket
>> returns
>> the Component.
>> So if there was a way to customize the nomenclature of what the "names" of
>> the fields are in a loop then it would be easy to refer to components via
>> name directly.
>>
>> ... I can't do [IN CONCEPT] get("additionalFeatures").get("<My naming
>> convention Sub Item component Id>").getDefaultModelObject() or something.
>> <-- I was asking if there was any magical way like that.
>>
>
> The question Igor asked isn't answered. WHY do you need to access the
> ListItem? For what purpose? From where in your code? Why? This is just
> regular java - access it as a reference to a java object if you must. But I
> don't see why you need to. Unless you're doing something wrong.
>
> Not a big deal , I worked around . For the sake of discussion my ListItem
>> is
>> defined by the following:
>>
>> ListView additionalFeatures = new ListView<String>("additionalFeatures",
>> additionalFeaturesKeyList) {
>> ...
>> @Override
>> protected void populateItem(ListItem<String> item)
>> {
>> String key = item.getModelObject();
>> //Assume this to be the Name / Id of
>> something
>> item.add(new Label("name", new
>> Model(key)));
>>
>> String modelKeyName =
>> MarshalUtils.toAlphaNumeric(key);
>> final Feature feature =
>> additionalFeaturesMap.get(key);
>> item.add(new TextArea("value", new
>> Model(feature.getValue().toString()))
>> .setLabel(new
>> Model(modelKeyName))
>> .setMarkupId(key));
>> }
>> ...
>> }
>>
>
> OH! There's where you're doing something wrong. Rather than allowing a
> model (or here, several models) to marshal your data for you (get the
> current value from the list, and the map, and finally from your pojo), you
> are doing it yourself. Using "new Model(...)" does *not* mean you are using
> models correctly. Your code above should be using property models to get
> the properties from the pojos. By doing this, the form fields will also set
> the updated values back on your pojos, which means you won't need to
> manually access these list items later. Try to avoid touching the domain
> object at all in your component creation code (only let the models touch
> it).
>
> What I went with at the end was:
>>
>> ListView listView =
>> (ListView)get("additionalFeatures");
>> for (int x=0;
>> x<listView.size(); x++) {
>> ListItem
>> additionalFeatureField = (ListItem)listView.get(x);
>>
>> //Now I
>> work
>> with the ListItem however I want to and derive what I want :)
>>
>
> Well, I would say "where are you doing that?" which was basically the
> original question - where would you need to access the list item directly?
> But, from looking at the code above, I'll bet that you are doing this loop
> over list items in your form onSubmit or similar. Again, this is horrible.
> You shouldn't be doing that. The form fields should have models that set
> the data on the pojo for you. Then you don't need to iterate through them
> and marshal data yourself.
>
> ..Which works also, but not as elegant as I hoped. But I realize its a
>> LIST,
>> so my expectations are perhaps unjustified and iteration of the list is
>> logical and inescapable.
>>
>
> No - iteration of the list is not necessary, and *very* escapable!
>
> --
> Jeremy Thomerson
> http://wickettraining.com
> *Need a CMS for Wicket? Use Brix! http://brixcms.org*
>
>
>
PS - meant to include a link to this page, which may help you understand
models: https://cwiki.apache.org/WICKET/working-with-wicket-models.html
Don't worry - it's probably the most common mistake Wicket newbs make! It's
definitely the thing I stress understanding the most in my Wicket classes.
--
Jeremy Thomerson
http://wickettraining.com
*Need a CMS for Wicket? Use Brix! http://brixcms.org*
Re: Changing/Accessing name of ListItem in ListView
Posted by Jeremy Thomerson <je...@wickettraining.com>.
On Sat, Jan 15, 2011 at 6:36 AM, Arjun Dhar <dh...@yahoo.com> wrote:
>
> I was hoping on the lines, where you do "get(<component id>)"; Wicket
> returns
> the Component.
> So if there was a way to customize the nomenclature of what the "names" of
> the fields are in a loop then it would be easy to refer to components via
> name directly.
>
> ... I can't do [IN CONCEPT] get("additionalFeatures").get("<My naming
> convention Sub Item component Id>").getDefaultModelObject() or something.
> <-- I was asking if there was any magical way like that.
>
The question Igor asked isn't answered. WHY do you need to access the
ListItem? For what purpose? From where in your code? Why? This is just
regular java - access it as a reference to a java object if you must. But I
don't see why you need to. Unless you're doing something wrong.
Not a big deal , I worked around . For the sake of discussion my ListItem is
> defined by the following:
>
> ListView additionalFeatures = new ListView<String>("additionalFeatures",
> additionalFeaturesKeyList) {
> ...
> @Override
> protected void populateItem(ListItem<String> item) {
> String key = item.getModelObject(); //Assume
> this to be the Name / Id of
> something
> item.add(new Label("name", new Model(key)));
>
> String modelKeyName =
> MarshalUtils.toAlphaNumeric(key);
> final Feature feature =
> additionalFeaturesMap.get(key);
> item.add(new TextArea("value", new
> Model(feature.getValue().toString()))
> .setLabel(new
> Model(modelKeyName))
> .setMarkupId(key));
> }
> ...
> }
>
OH! There's where you're doing something wrong. Rather than allowing a
model (or here, several models) to marshal your data for you (get the
current value from the list, and the map, and finally from your pojo), you
are doing it yourself. Using "new Model(...)" does *not* mean you are using
models correctly. Your code above should be using property models to get
the properties from the pojos. By doing this, the form fields will also set
the updated values back on your pojos, which means you won't need to
manually access these list items later. Try to avoid touching the domain
object at all in your component creation code (only let the models touch
it).
What I went with at the end was:
>
> ListView listView =
> (ListView)get("additionalFeatures");
> for (int x=0;
> x<listView.size(); x++) {
> ListItem
> additionalFeatureField = (ListItem)listView.get(x);
>
> //Now I work
> with the ListItem however I want to and derive what I want :)
>
Well, I would say "where are you doing that?" which was basically the
original question - where would you need to access the list item directly?
But, from looking at the code above, I'll bet that you are doing this loop
over list items in your form onSubmit or similar. Again, this is horrible.
You shouldn't be doing that. The form fields should have models that set
the data on the pojo for you. Then you don't need to iterate through them
and marshal data yourself.
..Which works also, but not as elegant as I hoped. But I realize its a LIST,
> so my expectations are perhaps unjustified and iteration of the list is
> logical and inescapable.
>
No - iteration of the list is not necessary, and *very* escapable!
--
Jeremy Thomerson
http://wickettraining.com
*Need a CMS for Wicket? Use Brix! http://brixcms.org*
Re: Changing/Accessing name of ListItem in ListView
Posted by Arjun Dhar <dh...@yahoo.com>.
I was hoping on the lines, where you do "get(<component id>)"; Wicket returns
the Component.
So if there was a way to customize the nomenclature of what the "names" of
the fields are in a loop then it would be easy to refer to components via
name directly.
... I can't do [IN CONCEPT] get("additionalFeatures").get("<My naming
convention Sub Item component Id>").getDefaultModelObject() or something.
<-- I was asking if there was any magical way like that.
Not a big deal , I worked around . For the sake of discussion my ListItem is
defined by the following:
ListView additionalFeatures = new ListView<String>("additionalFeatures",
additionalFeaturesKeyList) {
...
@Override
protected void populateItem(ListItem<String> item) {
String key = item.getModelObject(); //Assume this to be the Name / Id of
something
item.add(new Label("name", new Model(key)));
String modelKeyName = MarshalUtils.toAlphaNumeric(key);
final Feature feature = additionalFeaturesMap.get(key);
item.add(new TextArea("value", new Model(feature.getValue().toString()))
.setLabel(new Model(modelKeyName))
.setMarkupId(key));
}
...
}
What I went with at the end was:
ListView listView = (ListView)get("additionalFeatures");
for (int x=0; x<listView.size(); x++) {
ListItem additionalFeatureField = (ListItem)listView.get(x);
//Now I work
with the ListItem however I want to and derive what I want :)
...
}
..Which works also, but not as elegant as I hoped. But I realize its a LIST,
so my expectations are perhaps unjustified and iteration of the list is
logical and inescapable.
--
View this message in context: http://apache-wicket.1842946.n4.nabble.com/Changing-Accessing-name-of-ListItem-in-ListView-tp3218777p3219010.html
Sent from the Users forum mailing list archive at Nabble.com.
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@wicket.apache.org
For additional commands, e-mail: users-help@wicket.apache.org
Re: Changing/Accessing name of ListItem in ListView
Posted by Igor Vaynberg <ig...@gmail.com>.
why do you need to access the listitem? listitem.getmodelobject() will
give you the item in the list the item is pointed to.
-igor
On Fri, Jan 14, 2011 at 11:07 PM, Arjun Dhar <dh...@yahoo.com> wrote:
>
> Hi,
> when using a ListView, the name uses the following format to Render. <loop
> name>:<index>:<field id>
>
> In onSubmit(..); this is fine if you know the order of the list. However say
> if the primary data Structure is a hashmap then its more convenient/elegant
> to retrieve by Name. I can change the name of the attribute but Wicket does
> not recognize it when one does get(<componentId>).
>
> Using ListView.getList() I can access the Model, but this does not help
> getting the access to the individual components.
>
> Looks like the only way is to use a numberic counter and construct the
> Component ID's to access it one my one.
>
> Is there a way to change the component Id ..or perhaps access these by name?
> --
> View this message in context: http://apache-wicket.1842946.n4.nabble.com/Changing-Accessing-name-of-ListItem-in-ListView-tp3218777p3218777.html
> Sent from the Users forum mailing list archive at Nabble.com.
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@wicket.apache.org
> For additional commands, e-mail: users-help@wicket.apache.org
>
>
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@wicket.apache.org
For additional commands, e-mail: users-help@wicket.apache.org