fetch column parent :name instead of :parent_id

[zippax]

table do
    column :name
    column :parent_id
    actions
end

the second column will show the id. I want to show parent name instead of the id.

[slenderock]

Try this:

column :parent, ->(parent) { parent.name }
or 
column :parent, &:name

[zippax]

Hi @slenderock this will show me the current child name, I need to show the parent name

[slenderock]

Hello, @zippax
Sorry for that. I made a little typo

column :parent, ->(current_record) { current_record.parent&.name }

I guess "&" is required to prevent errors when parent doesn't exist for this record.
Hope this helps)

[zippax]

Error
undefined method 'parent'

if I change it to :parent_id will show me :

undefined method 'name' for 1:Fixnum

[slenderock]

undefined method 'parent'

for what class ?

[zippax]

column :parent, ->(current_record) { current_record.parent_id&.name }

ActionView::Template::Error at /categories
undefined method `name' for 1:Fixnum

[slenderock]

You should use active_record object(not id) if you want to get method #name.
So you need to change back #parent_id to #parent

If you get "undefined method 'parent'" you probably forgot to set belongs_to association in your model.
Please check this out.
It will be great if u can share github link where this problem produses

Btw, I have this line of code in my project and it works fine:

column :user, ->(current_record) { current_record.user.full_name }

[zippax]

Actually the Category model have name and parent_id so there is no association between 2 models. both are in the same table

=> Category(id: integer, name: string, parent_id: integer, created_at: datetime, updated_at: datetime)

[zippax]

this is a Github repo https://github.com/zippax/cs

[slenderock]

Seems like you don't have parent model at all. So how you want to get parent name, if you don't have this relation?

[zippax]

so I have to make subCategory model and make association between it and the Category model

[slenderock]

You should have this code for subcategory

  has_many :subcategories, class_name: 'Category', foreign_key: :parent_id
  belongs_to :parent, class_name: 'Category', inverse_of: :subcategories, optional: true

[slenderock]

and then you can use:

column :parent, ->(category) { category.parent&.name }

[spohlenz]

As @slenderock mentions, having the associations in place are the key to getting this working.

One thing I would add is that in many cases, you can drop the custom block all together and just use:

column :parent

This will automatically display the parent instance (if present) by finding a method from Trestle.config.display_methods that it responds to. This defaults to [:display_name, :full_name, :name, :title, :username, :login, :email] so you won't need to alter anything when using the name method.

It will also automatically link the name to a corresponding admin for the parent model, if it exists.