datagrid_csv.rb

class TimeEntryReportsController < ApplicationController

  def index
    @time_entry_report = TimeEntryReport.new(params[:time_entry_report])
    respond_to do |f|
      f.html do
        @assets = @time_entry_report.assets.page(params[:page])
      end
      f.csv do
        send_data @time_entry_report.to_csv, type: "text/csv", disposition: 'inline'
      end
    end
  end
end