diff options
Diffstat (limited to 'actionpack/lib/action_view/helpers/form_helper.rb')
| -rw-r--r-- | actionpack/lib/action_view/helpers/form_helper.rb | 84 |
1 files changed, 56 insertions, 28 deletions
diff --git a/actionpack/lib/action_view/helpers/form_helper.rb b/actionpack/lib/action_view/helpers/form_helper.rb index b8600fe445..6d97038da9 100644 --- a/actionpack/lib/action_view/helpers/form_helper.rb +++ b/actionpack/lib/action_view/helpers/form_helper.rb @@ -73,30 +73,54 @@ module ActionView # There are also methods for helping to build form tags in link:classes/ActionView/Helpers/FormOptionsHelper.html, # link:classes/ActionView/Helpers/DateHelper.html, and link:classes/ActionView/Helpers/ActiveRecordHelper.html module FormHelper - # Creates a form and a scope around a specific model object that is used as a base for questioning about - # values for the fields. + # Creates a form and a scope around a specific model object that is used as + # a base for questioning about values for the fields. # - # <% form_for :person, @person, :url => { :action => "update" } do |f| %> - # <%= f.error_messages %> - # First name: <%= f.text_field :first_name %> - # Last name : <%= f.text_field :last_name %> - # Biography : <%= f.text_area :biography %> - # Admin? : <%= f.check_box :admin %> + # Rails provides succint resource-oriented form generation with +form_for+ + # like this: + # + # <% form_for @offer do |f| %> + # <%= f.label :version, 'Version' %>: + # <%= f.text_field :version %><br /> + # <%= f.label :author, 'Author' %>: + # <%= f.text_field :author %><br /> # <% end %> # - # Worth noting is that the form_for tag is called in a ERb evaluation block, not an ERb output block. So that's <tt><% %></tt>, - # not <tt><%= %></tt>. Also worth noting is that form_for yields a <tt>form_builder</tt> object, in this example as <tt>f</tt>, which emulates - # the API for the stand-alone FormHelper methods, but without the object name. So instead of <tt>text_field :person, :name</tt>, - # you get away with <tt>f.text_field :name</tt>. Notice that you can even do <tt><%= f.error_messages %></tt> to display the - # error messsages of the model object in question. + # There, +form_for+ is able to generate the rest of RESTful parameters + # based on introspection on the record, but to understand what it does we + # need to dig first into the alternative generic usage it is based upon. + # + # === Generic form_for # - # Even further, the form_for method allows you to more easily escape the instance variable convention. So while the stand-alone - # approach would require <tt>text_field :person, :name, :object => person</tt> - # to work with local variables instead of instance ones, the form_for calls remain the same. You simply declare once with - # <tt>:person, person</tt> and all subsequent field calls save <tt>:person</tt> and <tt>:object => person</tt>. + # The generic way to call +form_for+ requires a few arguments: # - # Also note that form_for doesn't create an exclusive scope. It's still possible to use both the stand-alone FormHelper methods - # and methods from FormTagHelper. For example: + # <% form_for :person, @person, :url => { :action => "update" } do |f| %> + # <%= f.error_messages %> + # First name: <%= f.text_field :first_name %><br /> + # Last name : <%= f.text_field :last_name %><br /> + # Biography : <%= f.text_area :biography %><br /> + # Admin? : <%= f.check_box :admin %><br /> + # <% end %> + # + # Worth noting is that the +form_for+ tag is called in a ERb evaluation block, + # not an ERb output block. So that's <tt><% %></tt>, not <tt><%= %></tt>. Also + # worth noting is that +form_for+ yields a form builder object, in this + # example as +f+, which emulates the API for the stand-alone FormHelper + # methods, but without the object name. So instead of <tt>text_field :person, :name</tt>, + # you get away with <tt>f.text_field :name</tt>. Notice that you can even do + # <tt><%= f.error_messages %></tt> to display the error messsages of the model + # object in question. + # + # Even further, the +form_for+ method allows you to more easily escape the + # instance variable convention. So while the stand-alone approach would require + # <tt>text_field :person, :name, :object => person</tt> to work with local + # variables instead of instance ones, the +form_for+ calls remain the same. + # You simply declare once with <tt>:person, person</tt> and all subsequent + # field calls save <tt>:person</tt> and <tt>:object => person</tt>. + # + # Also note that +form_for+ doesn't create an exclusive scope. It's still + # possible to use both the stand-alone FormHelper methods and methods from + # FormTagHelper. For example: # # <% form_for :person, @person, :url => { :action => "update" } do |f| %> # First name: <%= f.text_field :first_name %> @@ -105,22 +129,26 @@ module ActionView # Admin? : <%= check_box_tag "person[admin]", @person.company.admin? %> # <% end %> # - # Note: This also works for the methods in FormOptionHelper and DateHelper that are designed to work with an object as base, - # like FormOptionHelper#collection_select and DateHelper#datetime_select. + # This also works for the methods in FormOptionHelper and DateHelper that are + # designed to work with an object as base, like FormOptionHelper#collection_select + # and DateHelper#datetime_select. # - # HTML attributes for the form tag can be given as <tt>:html => {...}</tt>. For example: + # HTML attributes for the form tag can be given as <tt>:html => {...}</tt>. + # For example: # # <% form_for :person, @person, :html => {:id => 'person_form'} do |f| %> # ... # <% end %> # - # The above form will then have the <tt>id</tt> attribute with the value </tt>person_form</tt>, which you can then - # style with CSS or manipulate with JavaScript. + # The above form will then have the +id+ attribute with the value "person_form", + # which you can then style with CSS or manipulate with JavaScript. # # === Relying on record identification # - # In addition to manually configuring the form_for call, you can also rely on record identification, which will use - # the conventions and named routes of that approach. Examples: + # As we said above, in addition to manually configuring the +form_for+ call, + # you can rely on record identification, which will use the conventions and + # named routes of that approach. This is the preferred way to use +form_for+ + # nowadays: # # <% form_for(@post) do |f| %> # ... @@ -140,7 +168,7 @@ module ActionView # # This will expand to be the same as: # - # <% form_for :post, @post, :url => posts_path, :html => { :class => "new_post", :id => "new_post" } do |f| %> + # <% form_for :post, Post.new, :url => posts_path, :html => { :class => "new_post", :id => "new_post" } do |f| %> # ... # <% end %> # @@ -150,7 +178,7 @@ module ActionView # ... # <% end %> # - # And for namespaced routes, like admin_post_url: + # And for namespaced routes, like +admin_post_url+: # # <% form_for([:admin, @post]) do |f| %> # ... |