Rails：使用has_many / Emirates_to关联创建对象

Question

There are two models Task and Project . A Project has many 'Task's and a 'Task' belongs_to a `Project'.

class Task < ActiveRecord::Base
  belongs_to :project
end

class Project < ActiveRecord::Base
  has_many :tasks
end

A list of all Task s is displayed as a separate page for each Project and displays your Task s.

How to create the condition for the method create , so that the Task be able to be created as an independent object, and associated with the Project ?

My knowledge was only enough to write two separate methods.

To create associated objects:

def create
  @project = Project.find(params[:project_id])
  @task = @project.tasks.create(task_params)
  redirect_to project_path(@project)
end

To create a separate object:

def create
  @task = current_user.tasks.new(task_params)

  respond_to do |format|
    if @task.save
      format.html { redirect_to @task, notice: 'Task was successfully created.' }
      format.js {}
      format.json { render json: @task, status: :created, location: @task }
    else
      format.html { render action: "new" }
      format.json { render json: @task.errors, status: :unprocessable_entity }
    end
  end
end

How to do it one method?

Answer 1

You have to pass in the project_id to your second method. Then you can add

@task.project_id = params[:project_id]

or something like that. If tasks always belongs to projects you may want to model them as a nested resource .

Answer 2

Task Controller:

def index
  @tasks = Task.all
  @task  = Task.new
end

def create
 @task = if params[:project_id]
   @project = Project.find(params[:project_id])
   @project.tasks.build(task_params)
 else
   Task.new(task_params)
 end
 ...

Project Model:

class Project < ActiveRecord::Base
  has_many :tasks, dependent: :destroy
  accepts_nested_attributes_for :tasks,
                      :allow_destroy => true
end

and in projects controller

private      
def project_params
      params.require(:project).permit(:name, ....., taks_attributes: [:id, .....,:_destroy])
end