Views and If Else conditions

Rails
1

Hello all,

How do I use nested if conditions in my views? I have something like

if(res.birthdate_status == “0”)
{
if(res.gender == “M” || res.gender==“F”)
print , //print a comma
print res.age
}

–
Regards

Haris G.

2

Well, you could do this, but I don’t like it:

<% if @user.birthdate_status == 0 %>
<% if @user.gender == “M” || @user.gender == “F” %>
,
<% end %>
<%[email protected] %>
<% end %>

However, Rails has helpers to make this kind of stuff a little more
organized.

In your view, do this:

<%=display_age(@user) %>

Then in helpers/application_helper.rb, add this code (untested and not
as
pretty as it could be)

def display_age(user)
result = “”
if user.birthday_status == 0
result = user.age
if user.gender == “M” || user.gender == “F”
result = “, #{result}” # the #{} syntax is for embedding
expressions
in strings
end
end
return result
end

Helpers keep your views clean. They’re a place to hide display logic.
Business logic should go in your model, so don’t buse helpers :slight_smile:

Does that help?

-Brian

3

Thanx brian, yeah it does help.

Please also tell me another thing. I have the following in my
index.rhtml

<% @result.each do |res| %>
<%= res.first_name %>


<%= res.register.language_speak %>





<% end %>

My models are as follows

class Profile < ActiveRecord::Base
has_many :friends, :foreign_key => “user_id”
has_one :register, :foreign_key => “id”

def self.table_name() “mhp_profile” end
end

class Friend < ActiveRecord::Base
belongs_to :profile

def self.table_name() “mhp_friends” end
end

class Register < ActiveRecord::Base
belongs_to :profile

def self.table_name() “mhp_register” end
end

But Im getting the following error.

Showing profile/index.rhtml where line #4 raised:

You have a nil object when you didn’t expect it!
The error occurred while evaluating nil.language_speak

Any idea what am I doing wrong…I have only one controller for profile
as
follows

class ProfileController < ApplicationController
def index
@result = Profile.find(:all)
end
end

On Jan 2, 2008 1:39 PM, Brian H. [email protected] wrote:

However, Rails has helpers to make this kind of stuff a little more
result = “”
Helpers keep your views clean. They’re a place to hide display logic.

Hello all,

–
Regards

Haris G.

–
Regards

Haris G.

4

On Jan 2, 2008, at 3:34 AM, Haris G. wrote:

Thanx brian, yeah it does help.

Please also tell me another thing. I have the following in my
index.rhtml

<% @result.each do |res| %>
<%= res.first_name %>


<%= res.register.language_speak %>

It sounds like you don’t have an associated “register” for this
“res”. A very simple solution is to test register, such as

<%= res.register.language_speak if res.register %>

or

<%= res.register.language_speak unless res.register.nil? %>

depending on how your mind likes to conceptualize things.

Peace,
Phillip

5

On Jan 2, 2008 8:07 AM, Phillip K. [email protected] wrote:

<%= res.first_name %>
<%= res.register.language_speak unless res.register.nil? %>

depending on how your mind likes to conceptualize things.

I’d be tempted to add a method on the profile model to return
language_speak (should this really be something like language_spoken
?).

class Profile
…
def language_speak
register.language_speak if register
end
end

and then change the view code to just:

<%= res.language_speak %>

The original code violates the so-called “law” of Demeter which says
you shouldn’t reach through an object to get to another one, the
canonical example of a demeter violation would be having a PaperBoy
object which grabs the Wallet object from one if its Customers to
extract payment for a subscription.

Besides the obvious rudeness, doing this with a method in the model
you have directly at hand isolates the view code from potential future
refactorings.

–
Rick DeNatale

My blog on Ruby
http://talklikeaduck.denhaven2.com/