Rails - Jan 2006 - Editing N instances of a model on one page

I have a situation where I want to edit an arbitrary number of instances 
of one model on one page.  I can and have accomplished this by manually 
managing the object <-> text field relationship, but in a way I consider 
at best hackish.  I''d like to know a clean way to do this.

If you want to edit the name attribute on a person class, you write code 
like this

text_field("person","name")

Say I have an array in variable @people.  What my mind feels is the 
logical thing to do is

for i in 0...n
  p = "people[" + i.to_s + "]"
  text_field(p,"name")
end

That might be the "ugly" way to do it but you get the idea.  I want to
put N text fields on the screen, each corresponding to the name 
attribute on a different person object.  However, that doesn''t work for
me.

Does anyone have a good/most-often-used idiom for doing this?  Help 
would be appreciated.  Thanks a lot.

I have read, but not experimented with 2d arrays for form fields, so
something like this may work -


for key, person in @people
  text_field(people[key],"name")
end

No guarantees on that, but worth investigating a bit further.

matt

On 1/16/06, Mike Harris <GENIE@prodigy.net> wrote:
>
> I have a situation where I want to edit an arbitrary number of instances
> of one model on one page.  I can and have accomplished this by manually
> managing the object <-> text field relationship, but in a way I
consider
> at best hackish.  I''d like to know a clean way to do this.
>
> If you want to edit the name attribute on a person class, you write code
> like this
>
> text_field("person","name")
>
> Say I have an array in variable @people.  What my mind feels is the
> logical thing to do is
>
> for i in 0...n
>   p = "people[" + i.to_s + "]"
>   text_field(p,"name")
> end
>
> That might be the "ugly" way to do it but you get the idea.  I
want to
> put N text fields on the screen, each corresponding to the name
> attribute on a different person object.  However, that doesn''t
work for
> me.
>
> Does anyone have a good/most-often-used idiom for doing this?  Help
> would be appreciated.  Thanks a lot.
>
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>
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It''s my understanding that for the text field helper, you put in a 
string representing the name of your object, and rails takes care of the 
mapping.  Here, you are putting the actual object in the field, which 
does not work.

Also, I''m not sure what you are referring to with 2D arrays, unless the
N objects are 1 dimension and the attributes are the second. 

Don''t mean to sound rude, just want to get to the bottom of this.  I 
find it hard to believe that Rails doesn''t have an idiom to support
this.

matthew clark wrote:
> I have read, but not experimented with 2d arrays for form fields, so 
> something like this may work -
>
>
> for key, person in @people
>   text_field(people[key],"name")
> end
>
> No guarantees on that, but worth investigating a bit further.
>
> matt
>
> On 1/16/06, *Mike Harris* <GENIE@prodigy.net 
> <mailto:GENIE@prodigy.net>> wrote:
>
>     I have a situation where I want to edit an arbitrary number of
>     instances
>     of one model on one page.  I can and have accomplished this by
>     manually
>     managing the object <-> text field relationship, but in a way I
>     consider
>     at best hackish.  I''d like to know a clean way to do this.
>
>     If you want to edit the name attribute on a person class, you
>     write code
>     like this
>
>     text_field("person","name")
>
>     Say I have an array in variable @people.  What my mind feels is the
>     logical thing to do is
>
>     for i in 0...n
>       p = "people[" + i.to_s + "]"
>       text_field(p,"name")
>     end
>
>     That might be the "ugly" way to do it but you get the idea. 
I
>     want to
>     put N text fields on the screen, each corresponding to the name
>     attribute on a different person object.  However, that doesn''t
>     work for me.
>
>     Does anyone have a good/most-often-used idiom for doing this?  Help
>     would be appreciated.  Thanks a lot.
>
>     _______________________________________________
>     Rails mailing list
>     Rails@lists.rubyonrails.org <mailto:Rails@lists.rubyonrails.org>
>     http://lists.rubyonrails.org/mailman/listinfo/rails
>
>
>------------------------------------------------------------------------
>
>_______________________________________________
>Rails mailing list
>Rails@lists.rubyonrails.org
>http://lists.rubyonrails.org/mailman/listinfo/rails
>  
>

Nobody else has ever done this?  I didn''t feel like this was a very 
uncommon operation. 

Mike Harris wrote:
> I have a situation where I want to edit an arbitrary number of 
> instances of one model on one page.  I can and have accomplished this 
> by manually managing the object <-> text field relationship, but in a
> way I consider at best hackish.  I''d like to know a clean way to
do this.
>
> If you want to edit the name attribute on a person class, you write 
> code like this
>
> text_field("person","name")
>
> Say I have an array in variable @people.  What my mind feels is the 
> logical thing to do is
>
> for i in 0...n
>  p = "people[" + i.to_s + "]"
>  text_field(p,"name")
> end
>
> That might be the "ugly" way to do it but you get the idea.  I
want to
> put N text fields on the screen, each corresponding to the name 
> attribute on a different person object.  However, that doesn''t
work
> for me.
>
> Does anyone have a good/most-often-used idiom for doing this?  Help 
> would be appreciated.  Thanks a lot.
>
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>

Mike Harris wrote:
> It''s my understanding that for the text field helper, you put in a
> string representing the name of your object, and rails takes care of the
> mapping.  Here, you are putting the actual object in the field, which
> does not work.
> 
> Also, I''m not sure what you are referring to with 2D arrays,
unless the
> N objects are 1 dimension and the attributes are the second.
> 
> Don''t mean to sound rude, just want to get to the bottom of this. 
I
> find it hard to believe that Rails doesn''t have an idiom to
support
> this.
I, too, am looking for an elegant solution to this.

Without something built-in to text_field, there''s a lot of manual work 
to do getting the errors indicated properly.

Still searching.

   Jake

-- 
Posted via http://www.ruby-forum.com/.

Check out p356 of the rails book.

<% for @person in @people%>
  <%= text_field(''person[]'', ''name'')
%>
<% end  %>

"params[:person] will be a hash of hashes, where each key is the id of
a model object and the corresponding value are the values from the
form for that object.  In the controller, this could be used to update
all person rows with something like
Person.update(params[:person].keys, params[:person].values)"



On 1/16/06, Mike Harris <GENIE@prodigy.net> wrote:
> I have a situation where I want to edit an arbitrary number of instances
> of one model on one page.  I can and have accomplished this by manually
> managing the object <-> text field relationship, but in a way I
consider
> at best hackish.  I''d like to know a clean way to do this.
>
> If you want to edit the name attribute on a person class, you write code
> like this
>
> text_field("person","name")
>
> Say I have an array in variable @people.  What my mind feels is the
> logical thing to do is
>
> for i in 0...n
>   p = "people[" + i.to_s + "]"
>   text_field(p,"name")
> end
>
> That might be the "ugly" way to do it but you get the idea.  I
want to
> put N text fields on the screen, each corresponding to the name
> attribute on a different person object.  However, that doesn''t
work for me.
>
> Does anyone have a good/most-often-used idiom for doing this?  Help
> would be appreciated.  Thanks a lot.
>
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>

Pat Maddox wrote:
> Check out p356 of the rails book.
> 
> <% for @person in @people%>
>   <%= text_field(''person[]'', ''name'')
%>
> <% end  %>
> 
> "params[:person] will be a hash of hashes, where each key is the id of
> a model object and the corresponding value are the values from the
> form for that object.  In the controller, this could be used to update
> all person rows with something like
> Person.update(params[:person].keys, params[:person].values)"
Thanks!  That works great.  I knew I saw this somewhere, but had a 
really hard time tracking it down again.

Now, when the text_fields are rendered, it seems they won''t
"markup"
errors in more than one model -- or even more than one instance of a 
model.  So, I only see errors in one instance at a time.

Is there a way to get it to mark up all instances?  Where is this action 
performed?

   Jake

-- 
Posted via http://www.ruby-forum.com/.

On 1/26/06, Jake Janovetz <jakejanovetz@yahoo.com>
wrote:
> Pat Maddox wrote:
> > Check out p356 of the rails book.
> >
> > <% for @person in @people%>
> >   <%= text_field(''person[]'',
''name'') %>
> > <% end  %>
> >
> > "params[:person] will be a hash of hashes, where each key is the
id of
> > a model object and the corresponding value are the values from the
> > form for that object.  In the controller, this could be used to update
> > all person rows with something like
> > Person.update(params[:person].keys, params[:person].values)"
>
> Thanks!  That works great.  I knew I saw this somewhere, but had a
> really hard time tracking it down again.
>
> Now, when the text_fields are rendered, it seems they won''t
"markup"
> errors in more than one model -- or even more than one instance of a
> model.  So, I only see errors in one instance at a time.
>
> Is there a way to get it to mark up all instances?  Where is this action
> performed?
>
I''ve done this in partials before.
Assuming the partial is named _example.rhtml, and the model class is Example:
(This assumes that the partial builds up a table, but that''s not
required.)

<% @example = example -%>
<% if @example.errors.count > 0 then -%>
  <tr><td colspan="8">
  <%= error_messages_for ''example'', :id =>
"errorExplanation#{example_counter}" %>
  </td></tr>
<% end -%>
# other table-related gunk goes here.
<%= text_field ''example'', ''something'',
''index'' => example_counter %>
# end of partial

In the calling view, you''d do:
<%= render :partial => ''example'', :collection =>
@examples %>

render_partial_collection sets up the counter variable that prevents
the error messages from stomping on each other. If any particular
Example instance has errors, your partial will create a table row for
it and put the error messages there.