Rails%203%20In%20Action

Changing a ticket’s state
There you have it! The State model is up and running. Let’s now
associate this class with the Comment class by adding this line to the
top of the Comment model’s definition:
belongs_to :state
The state method provided by this belongs_to will be used shortly to display the
state on the ticket page, as in figure 10.6.
Before doing that, however, you need to add the select box for the state to the
comment form.
10.2.2 Selecting states
In the comment form partial, add this select box underneath the text box, as shown in
the following listing.
@ticket.state_id %>
Listing 10.11 app/views/comments/_form.html.erb
Here you use a new method, select, which takes its first argument as the foreign-key
attribute of your Comment object, not the association. You also use the :state_id value
for the argument passed to the label, but Rails is smart enough to know the text for
this should be “State”. select’s second argument is a two-dimensional 3 Array that you
create by using map on the State objects returned from the controller in the @states
variable. The first element of each array is the value you want shown as an option in
the select box to the user, whereas the second element is the value that’s passed back
to the controller.
Use the :selected option in the select call to select the current state of the ticket
from the list. This value must match the value argument for one of the options in the
select box; otherwise it will default to the first option.
Let’s assume for a moment that you’ve got three states: New, Open, and Closed.
For a ticket that has its state set to New, the select box generated by f.select would
look like this:
New
Open
Closed
3 A two-dimensional array is an array that contains arrays as elements.
Figure 10.6
A ticket’s state
255