I'm currently learning MVC2, and I have seen three variants of the tags that contain the actual code for a View:
<% ... %>
With a = after the %
<%= ... %>
and with a : after the %
<%: ... %>
What is the difference of these three code containers?
And are there any other variants of these?
<% ... %>
is just a block of code
<%: "blah blah" %>
Is Shorthand for
<%= Html.Encode("blah blah") %>
Which is shorthand for
<% Response.Write(Html.Encode("blah blah")) %>
1.<% ... %> just block of code
<%if (Model.HelloWorld != null){%>
Hello World!!
<%} %>
2.<%= ... %> plain text without escaping
<%=Model.HelloWorld %>
3.<%: ... %> text with escaping equal <%= Server.HtmlEncode(Model.Something) %> Details here
<%:Model.HelloWorld %>
Related
I'm using Skeleton for my 16 columns grid system on Silverstripe.
My code below:
<% loop $AllChildren %>
<div class="three columns"><h5>$Title</h5></div>
<% end_loop %>
produces:
Children1 Children2 Children3 Children4 Children5
Children6 Children7 Children8 Children9 Children10
My question is how do I put a space between the rows so the output will
be like:
Children1 Children2 Children3 Children4 Children5
Children6 Children7 Children8 Children9 Children10
In SS3 you can use $MultipleOf() (api docs) in your templates to output something every nth item, e.g.
<% loop $AllChildren %>
<div class="three columns"><h5>$Title</h5></div>
<% if $MultipleOf(5) %>
<hr class="extra-space">
<% end_if %>
<% end_loop %>
I know about partial in rails, but it seems that I can only re-use exactly the same form with partial.
What if I have two forms that differ only in one field? For example, in my classroom app, I have one form for a peer-grader and one form for a teacher-grader.
The teacher's form is as follows. The peer-grader form is exactly the same, minus the grade field. How do I DRY this?
<%= form_for #doc,
url: student_homework_document_path(student_id: #doc.submitter_id,
id: #doc.id),
html: { multipart: true } do |f| %>
<%= render 'shared/error_messages', object: f.object %>
<%= f.label :grade %>
<%= f.number_field :grade %>
<%= f.label :graded_file %>
<%= f.file_field :graded_file %>
<%= f.label :graded_file_source_code %>
<%= f.file_field :graded_file_source_code %>
<%= f.submit "Submit grading", class: "btn btn-large" %>
<% end %>
I would have thought you had one controller called teachers and one called peers or something. You could keep the form the same but add a variable to the peer-grader method such as #peer_grader = true. Then in your form add:
<% if #peer_grader = true %>
<%= f.label :grade %>
<%= f.number_field :grade %>
<% end %>
You would also need to set another variable called #url in both controllers set to the correct path and then update the form to:
<%= form_for #doc, url: #url, html: { multipart: true } do |f| %>
I've been stuck on this problem for a couple of days now.
I've have some success with Railscasts Episode #198, but that one is for Rails 2. There have been some changes in Rails 3 that make it so the code provided in Episode #198 won't work.
The problem lies within the edit_individual.html.erb:
Original Code (provided by Ryan # Railscasts):
<% form_tag update_individual_products_path, :method => :put do %>
<% for product in #products %>
<% fields_for "products[]", product do |f| %>
<h2><%=h product.name %></h2>
<%= render "fields", :f => f %>
<% end %>
<% end %>
<p><%= submit_tag "Submit" %></p>
<% end %>
Modified Code (simply changed fields_for to form_for):
<% form_tag update_individual_products_path, :method => :put do %>
<% for product in #products %>
<% form_for "products[]", product do |f| %>
<h2><%=h product.name %></h2>
<%= render "fields", :f => f %>
<% end %>
<% end %>
<p><%= submit_tag "Submit" %></p>
<% end %>
In the new code, each record is placed within a form of their own, all inside one single form (which is the one I only want).
My question is, how can I get the code provided by Railscasts Episode #198 to work in Rails 3?
Here is a link to the Railscast I mentioned:
http://railscasts.com/episodes/198-edit-multiple-individually
Thank You,
c.allen.rosario
I found the solution. Just need to modify the following line in the code provided by Ryan # Railscasts:
<% fields_for "products[]", product do |f| %>
and change it to:
<%= fields_for "products[]", product do |f| %>
Notice, that the <% has been modified to <%=.
final solution:
<% form_tag update_individual_products_path :method => :put do %>
<% for product in #products %>
<%= fields_for "products[]", product do |f| %>
<h2><%= h product.name %></h2>
<% end %>
<% end %>
<p><%= submit_tag "Submit" %></p>
<% end %>
I was wondering if anyone could explain this solution to me. From what I understand you should only need a <% in front of the fields_for.
c.allen.rosario
The change in Rails 3 from <% fields_for to <%= fields_for is because it was confusing that form_for, form_tag, etc... were using <% form... %> even though they they were outputting html code.
With Rails 3, since they output html code, they use <%=.
Please note that your first line is deprecated:
<% form_tag update_individual_products_path, :method => :put do %>
should be
<%= form_tag update_individual_products_path, :method => :put do %>
Same for all form tags.
Hi I have any form with nested form, for example
<% form_for :main do |f| %>
trying to insert code here
<% fields_for :nested do |nested_form| %>
<%= nested_form.text_field :description %>
<% end %>
<% end %>
And then I am trying to insert anything to a main form, nested form doesn't produce any output. It outputs only when it is the only object in main form. Any suggestions?
From the Rails 3 documentation examples you need to write your form_for like this:
<%= form_for :main do |f| %>
# trying to insert code here
<%= fields_for :nested do |nested_form| %>
<%= nested_form.text_field :description %>
<% end %>
<% end %>
Note the <%= for both form_for and fields_for
The title contain my whole question.
<% /* Is a codeblock */ for(int i = 0;i<5;i++) { } %>
<%= "Writes something to the output stream" /* Response.Write */ %>
<%: "HTML-encodes this <b>hello</b> to the output stream" %>
For a good explanation about the <%, <%= and <%# syntax and their usage, please read this article.
The <%: syntax is new in .Net 4 and is used for encoding HTML output. See this article of ScottGu for more information about that.
<% %> is used just to execute server side code
ex. <% if(oject){...} %>
<%= %> is used execute server side code and return value
ex. <%=Html.Encode(Item["Name"]) %>
<%: %> is used execute server side code but it will return Html
Encoded string
ex. <%Item["Name"] %>
Source : What is difference between these tags <%, <%: , and <%= in ASP.NET MVC 2?