erlang - Nitrogen - 动态创建事件

Question

我是 Erlang/Nitrogen 的初学者。我正在玩弄一个由 mnesia 数据库支持的投标系统。在我的索引页面上，我有以下代码，各种项目及其属性是从数据库动态创建的:

%% -*- 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). 

我尝试以相同的方式创建我的事件，但没有成功。在我的代码中，警报将被替换为包含接受投标表格的灯箱。请帮助并告诉我我做错了什么。

Answer 1

据我所知，您使用“事件”在页面中捕获事件。

所以我会尝试类似的东西:

postback={bid, Index} 

然后用 :

捕获它

event({bid, Index})-> 
 %% do stuff
 ok;
event(_)->
 ok.

更新:

这只是您如何修复它的一个示例，它不是最好的方法。

%% -*- 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.