Schienen collection_select meine Sammlung gedruckt werden soll

Question

ich einen Fehler habe bei dem Versuch, collection_select zu verwenden;)

Ich habe diesen Code in meiner Sicht:

<%= f.collection_select(:channel, :channel_id, @channels, :id, :channelname, prompt: true) %> 

in meinem Controller Ich habe dies:

@channels = Channel.all 

und ich habe diesen Fehler:

undefined method `merge' for :channelname:Symbol 

Was ist mein Fehler?

Danke an alle!

Answer 1

Nach der Dokumentation:

collection_select(method, collection, value_method, text_method, options = {}, html_options = {}) public

So deshalb sollten Sie verwenden:

<%= f.collection_select(:channel_id, Channel.all, :id, :channelname, prompt: true) %> 

Answer 2

können Sie verwenden, wie

Channel.all.pluck(:id, :channelname) 

Zum Beispiel bei unten schauen nehmen

collection_select(
    :post, # field namespace 
    :author_id, # field name 
    # result of these two params will be: <select name="post[author_id]">... 

    # then you should specify some collection or array of rows. 
    # It can be Author.where(..).order(..) or something like that. 
    # In your example it is: 
    Author.all, 

    # then you should specify methods for generating options 
    :id, # this is name of method that will be called for every row, result will be set as key 
    :name_with_initial, # this is name of method that will be called for every row, result will be set as value 

    # as a result, every option will be generated by the following rule: 
    # <option value=#{author.id}>#{author.name_with_initial}</option> 
    # 'author' is an element in the collection or array 

    :prompt => true # then you can specify some params. You can find them in the docs. 
) 

Answer 3

versuchen, diese

<%= f.collection_select(:channel_id, :id, prompt: true) %>