Retrieving #dropdown selection in nitrogen framework - erlang

Question

I'm using the erlang nitrogen web framework to develop an application.
I must be missing something really simple, but I cannot figure out how to retrieve the selection made by a #dropbox element. It doesn't seem to get passed by the postback message. Does it maybe require some use of the wf:wire/3 function?
I haven't seen any documentation or examples that demonstrates this. The only examples I can find will just show the postback value which doesn't give any information about which option was selected.

Answer 1

You need to:
add an html_name to the dropbox,
add code to submit your form,
then in the called page (defined in the submit action) you can access to the value with wf:m(dropbox_name).
there a complete example at http://nitrogenproject.com/demos/restful

Answer 2

It depends on how you're using the dropdown. If you're using it in a restful "traditional form" non-ajaxy kind of manner, then the restful elements as mentioned by Pascal are the way to go.
However, if you're using them using Nitrogen's postback functionality, you want to simply define them by the more standard Nitrogen id.
body() ->
[
#dropdown{id=fruit, options=[
#option{text="Apple"},
#option{text="Banana"},
#option{text="Orange"}
]},
#button{text="Submit",postback=do_fruit}
].
event(do_fruit) ->
SelectedFruit = wf:q(fruit),
wf:wire(#alert{text="Selected Fruit was " ++ SelectedFruit}).
Note, the id of the dropdown is fruit. The #button initiates a postback with the value do_fruit, which matches in the event(do_fruit) function, and wf:q(fruit) retrieves the value of the submission with the id fruit.