Nitrogen - Dynamically creating Events - erlang

Question

I am a beginner with Erlang/Nitrogen.
I am toying with a bidding system back by a mnesia db.
On my index page I have the following code and the various items and their properties get created dynamically from the database:
%% -*- mode: nitrogen -*-
-module (index).
-compile(export_all).
-include_lib("nitrogen/include/wf.hrl").
main() -> #template { file="./site/templates/bare.html" }.
title() -> "Meir Panim Gala Dinner silent auction".
body() ->
Header = [#panel{id=header, body=[#h1{text="Meir Panim Gala Dinner silent auction"}]}],
{atomic, Items} = item_database:get_all(),
Elements = lists:map(fun(X) ->
{item, Index, Title, _, Picture, _, _, Reserve, CurrentBid} = X,
#panel{id=items, body=[
#span{id=title, text=Title},
#image{id=image, image= "images/" ++ Picture},
#span{id=currentbid, text="Current bid: £" ++ integer_to_list(CurrentBid)},
#span{id=reserve, text="Reserve: £" ++ wf:to_list(Reserve)},
#link{id=showalert, text="More info / Place your bid", postback="showalert"++integer_to_list(Index)}
]
}
end, Items),
wf:f([Header, Elements]).
{atomic, Items} = item_database:get_all(),
Actions = lists:map(fun(X) ->
{item, Index, _, _, _, _, _, _, _} = X,
event("showalert"++integer_to_list(Index)) ->
wf:wire(#alert{text="action "++integer_to_list(Index)++" clicked"})
end, Items).
I tried to create my events in the same manner but it was not working.
In my code the alerts will be replaced with lightboxes containing a form to accept bids.
Please help and tell me what I am doing wrong.

Answer 1

As far as I know you catch events in page with "event".
so I would try something like :
postback={bid, Index}
and at down catch it with :
event({bid, Index})->
%% do stuff
ok;
event(_)->
ok.
update:
this is only an example of how you can fix it, its not the best way.
%% -*- mode: nitrogen -*-
-module (index).
-compile(export_all).
-include_lib("nitrogen/include/wf.hrl").
main() -> #template { file="./site/templates/bare.html" }.
title() -> "Meir Panim Gala Dinner silent auction".
body() ->
Header = [#panel{id=header, body=[#h1{text="Meir Panim Gala Dinner silent auction"}]}],
{atomic, Items} = item_database:get_all(),
Elements = lists:map(fun(X) ->
{item, Index, Title, _, Picture, _, _, Reserve, CurrentBid} = X,
#panel{id=items, body=[
#span{id=title, text=Title},
#image{id=image, image= "images/" ++ Picture},
#span{id=currentbid, text="Current bid: £" ++ integer_to_list(CurrentBid)},
#span{id=reserve, text="Reserve: £" ++ wf:to_list(Reserve)},
#link{id=showalert, text="More info / Place your bid", postback={bid,Index}}
]
}
end, Items),
wf:f([Header, Elements]).
event({bid, Idx})->
%% you would better have a function to get one item at a time in item_database
case item_database:get_by_index(Idx) of
{atomic, X} ->
%% This is not the right way, use records
{item, Index, Title, _, Picture, _, _, Reserve, CurrentBid} = X,
wf:wire(#alert{text="action "++ Title ++" clicked"});
_ ->
wf:wire(#alert{text="item not found"})
end;
event(_)->
ok.

Answer 2

%% -*- mode: nitrogen -*-
-module (index).
-compile(export_all).
-include_lib("nitrogen/include/wf.hrl").
main() -> #template { file="./site/templates/bare.html" }.
title() -> "Welcome to Nitrogen".
body() ->
{atomic, Records} = item_database:get_all(),
Elements = lists:map(fun(X) ->
{item, Index, Title, _, _, _, _, _, _} = X,
#panel{body=[
#span{text=Title, style="font-size: 20px; font-weight: bold;"},
#br{},
#link{text="more info / place your bid", postback="showinfo"++integer_to_list(Index)},
#br{},
#link{text="register your bid", postback="registerbid"++integer_to_list(Index)},
#br{},
#br{},
#lightbox{id="lightbox"++integer_to_list(Index), style="display: none;", body=[
#span{text=Title, style="font-size: 24px; font-weight: bold; color: #ffffff;"}
]}
]}
end, Records),
wf:f([Elements]).
event(Event) ->
case (re:run(Event, "showinfo")) of
{match, _} ->
[_, _, SI] = re:split(Event, "(showinfo)"),
ShowIndex = binary:bin_to_list(SI),
wf:wire(#show{target="lightbox"++ShowIndex});
_ -> ok
end,
case (re:run(Event, "registerbid")) of
{match, _} ->
[_, _, RI] = re:split(Event, "(registerbid)"),
RegisterIndex = binary:bin_to_list(RI),
wf:wire(#alert{text="registerbid"++RegisterIndex++" clicked"});
_ -> ok
end.