Rails has got some nice default form options available in the FormHelper, however the check_box still leaves a little to be desired. It's great if you have one or two disparate elements, but what about when you want people to choose from a list of items like the following?
Code
<form>
Choose your favorite fruits.
<div><input value="apple" id="apple" name="fruit" type="checkbox"><label for="apple">Apple</label></div>
<div><input value="orange" id="orange" name="fruit" type="checkbox"><label for="orange">Orange</label></div>
<div><input value="banana" id="banana" name="fruit" type="checkbox"><label for="banana">Banana</label></div>
</form>
In the example above, they all have the name fruit which means that if you choose all of them and submit them to the server, you will get the parameter string
"fruit=apple&fruit=orange&fruit=banana"
All well and good, except when you are in the controller and you try and get the value of fruit (params[:fruit]), you will not get an array with the values of ["apple", "orange", "banana"]. You will only get "banana".
I like bananas as much as the next guy, but I want all the fruit...
So how do you do this?
It appears you have to explicitly tell Rails that it is an array. You can do this by using the square brackets "[]"
Code
<form>
Choose your favorite fruits.
<div><input value="apple" id="apple" name="fruit[]" type="checkbox"><label for="apple">Apple</label></div>
<div><input value="orange" id="orange" name="fruit[]" type="checkbox"><label for="orange">Orange</label></div>
<div><input value="banana" id="banana" name="fruit[]" type="checkbox"><label for="banana">Banana</label></div>
</form>
Now when you call params[:fruit], you will get the array ["apple", "orange", "banana"].
Note that this will work with any other type of elements as well (as long as there is a [] directive to turn them into an array).
Code
<form>
Choose your favorite fruits.
<div><input value="apple" id="apple" name="fruit" type="checkbox"><label for="apple">Apple</label></div>
<div><input value="orange" id="orange" name="fruit" type="checkbox"><label for="orange">Orange</label></div>
<div><input value="banana" id="banana" name="fruit" type="checkbox"><label for="banana">Banana</label></div>
</form>
In the example above, they all have the name fruit which means that if you choose all of them and submit them to the server, you will get the parameter string
"fruit=apple&fruit=orange&fruit=banana"
All well and good, except when you are in the controller and you try and get the value of fruit (params[:fruit]), you will not get an array with the values of ["apple", "orange", "banana"]. You will only get "banana".
I like bananas as much as the next guy, but I want all the fruit...
So how do you do this?
It appears you have to explicitly tell Rails that it is an array. You can do this by using the square brackets "[]"
Code
<form>
Choose your favorite fruits.
<div><input value="apple" id="apple" name="fruit[]" type="checkbox"><label for="apple">Apple</label></div>
<div><input value="orange" id="orange" name="fruit[]" type="checkbox"><label for="orange">Orange</label></div>
<div><input value="banana" id="banana" name="fruit[]" type="checkbox"><label for="banana">Banana</label></div>
</form>
Now when you call params[:fruit], you will get the array ["apple", "orange", "banana"].
Note that this will work with any other type of elements as well (as long as there is a [] directive to turn them into an array).
Comments
I had the same problem and this helped me solve it fast.
One thing to note, you can't use a symbol for the name when doing this. You have to use quotes.
check_box_tag :fruit[] won't work while
check_box_tag "fruit[]" will.
$fruits = $_POST["fruit"];
for ($i=0; $i";
}