Posted by
ihower
on
July 24, 2010
In partial view, we can use the instance variable directly, but it may be confused and make it hard to reuse anywhere, because we don't know exactly which instance variable can be used, so use the local variable in partial with explicitly assignment.
A partial is a reusable view template, it allow you to modularize the components which make up a particular page into logical, cohesive pieces. When required data is not passed into a partial, it is often difficult to reuse or change later.
By passing the required data in as locals you create self-documenting requirements for each view partial. It also helps to see where else it is rendered and what locals are required.
Bad Smell
class PostsController < ApplicationController
def show
@post = Post.find(params[:id])
end
end
<%= render :partial => "sidebar" %>
In this example, the partial sidebar can use the instance variable @post, but we can't know what's the instance variable @post without checking the controller codes. Let's use the local variable instead.
Refactor
<%= render :partial => "sidebar", :locals => { :post => @post } %>
or
<%= render "sidebar", :post => @post %>
Now we can use the local variable post in partial, it is much simpler.
Comments
<%=render "sidebar",:post => @some_other_instance_variable%>
@post=10
render :partial => 'new',:post => @post
new.html
<%=puts params[:post]%>
params[:post] is displayed the nil value.i want to pass the local values from controller to view file. Is there any other solutions for that?
I ran into a similar issue and I resolved this with
render :partial => 'new', :locals => {:post => @post}
I believe the issue is that you're passing in 2 hashes but it's getting interpreted as one. You could probably also possibly fix this by wrapping the two hashes in curly braces. I found adding 'locals' worked for me though.