how to generate barcode in c# net with example Adding the observe_form Helper to app/views/events/new.rhtml in Font

Make QR-Code in Font Adding the observe_form Helper to app/views/events/new.rhtml

Listing 7-12. Adding the observe_form Helper to app/views/events/new.rhtml
QR Code ISO/IEC18004 Drawer In None
Using Barcode generation for Font Control to generate, create QR image in Font applications.
www.OnBarcode.com
Paint UPC Code In None
Using Barcode printer for Font Control to generate, create UPC Symbol image in Font applications.
www.OnBarcode.com
<h1>New event</h1> <% form_tag({:action => 'create'}, :id => "event_form") do %> <%= render :partial => 'form' %> <%= submit_tag_or_cancel "Create" %>
Data Matrix 2d Barcode Creator In None
Using Barcode printer for Font Control to generate, create Data Matrix ECC200 image in Font applications.
www.OnBarcode.com
Drawing Barcode In None
Using Barcode creator for Font Control to generate, create Barcode image in Font applications.
www.OnBarcode.com
CHAPTER 7 IMPROVING INTERACTION WITH AJAX
PDF-417 2d Barcode Generator In None
Using Barcode creator for Font Control to generate, create PDF417 image in Font applications.
www.OnBarcode.com
Paint UCC - 12 In None
Using Barcode creation for Font Control to generate, create UCC.EAN - 128 image in Font applications.
www.OnBarcode.com
<% end %> <%= observe_form "event_form", :frequency => 1, :update => {}, :url => { :controller => 'events', :action => "observe_new" } %>
QR Code JIS X 0510 Maker In None
Using Barcode printer for Font Control to generate, create QR Code image in Font applications.
www.OnBarcode.com
Encoding USPS PLANET Barcode In None
Using Barcode creation for Font Control to generate, create Planet image in Font applications.
www.OnBarcode.com
In Listing 7-12, we changed the form_tag call, adding the :id parameter so that the created form can be referenced by our soon-to-exist Observer object. We used the observe_form helper with a few options, indicating the id of the form on which it must act. The first option is the URL of the action to which we ll send an Ajax call. The second option is the frequency, which indicates the amount of time, in seconds, at which changes to the form will be detected. If the frequency value is 0 or less, it will indicate to the Observer object that we will use event-based observation, and the Ajax call will be made after the user moves the focus out of each text box. With those small changes, as you start entering data in the new event form, you ll be able to see that Ajax requests are being made to the server. To prove this, run the application and take a look at the command prompt window where your web server is running. You should see requests like the following:
QR Generator In .NET
Using Barcode creation for .NET Control to generate, create QR Code 2d barcode image in VS .NET applications.
www.OnBarcode.com
QR-Code Creator In Java
Using Barcode maker for BIRT reports Control to generate, create QR-Code image in BIRT reports applications.
www.OnBarcode.com
Processing EventsController#observe_new (for 127.0.0.1) [POST] Session ID: 51b4bb0ab45219045ff0630128618f7c Parameters: {"commit"=>"Create", "tags"=>"", "event"=>{"occurs_on(1i)"=>"2007", "occurs_on(2i)"=>"5", "title"=>"RailsConf 2008", "occurs_on(3i)"=>"20", "url"=>"http://railsconf.com", "description"=>"", "location"=>"Nobody knows"}, "action"=>"observe_new", "categories"=>["1"], "controller"=>"events"}
Print QR In .NET Framework
Using Barcode drawer for Reporting Service Control to generate, create QR Code 2d barcode image in Reporting Service applications.
www.OnBarcode.com
EAN 128 Decoder In Visual C#
Using Barcode recognizer for VS .NET Control to read, scan read, scan image in .NET framework applications.
www.OnBarcode.com
In the controller, we need to create a method to receive the Ajax call from the
Print Code 39 Full ASCII In None
Using Barcode generator for Online Control to generate, create Code 39 Extended image in Online applications.
www.OnBarcode.com
Creating Data Matrix ECC200 In Objective-C
Using Barcode encoder for iPhone Control to generate, create DataMatrix image in iPhone applications.
www.OnBarcode.com
Observer object. The method will be called observe_new. Inside this method, we read all the parameters from the request and save the draft event to the session. Add the code shown in Listing 7-13 to the events controller.
QR Code JIS X 0510 Drawer In None
Using Barcode creator for Software Control to generate, create Quick Response Code image in Software applications.
www.OnBarcode.com
PDF417 Generator In Java
Using Barcode generation for BIRT reports Control to generate, create PDF 417 image in Eclipse BIRT applications.
www.OnBarcode.com
Listing 7-13. Adding the observe_new Action to app/controllers/events_controller.rb
Scanning Barcode In Java
Using Barcode Control SDK for Eclipse BIRT Control to generate, create, read, scan barcode image in Eclipse BIRT applications.
www.OnBarcode.com
EAN 13 Printer In Visual Studio .NET
Using Barcode encoder for ASP.NET Control to generate, create EAN 13 image in ASP.NET applications.
www.OnBarcode.com
def observe_new session[:event_draft] = current_user.events.build(params[:event]) render :nothing => true end
Code-128 Drawer In VS .NET
Using Barcode generation for .NET framework Control to generate, create Code 128 Code Set B image in VS .NET applications.
www.OnBarcode.com
Scan Code39 In Visual Studio .NET
Using Barcode decoder for VS .NET Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
CHAPTER 7 IMPROVING INTERACTION WITH AJAX
The observe_new method creates a new Event object with the request parameters, saves that object to the session, and finishes without rendering a response.
Note If you want to save the event in case the browser somehow crashes while the user is entering the
event information, you can take the same approach, but save the draft event to a cookie. The cookies interface is the same as session.
With the event information saved in the session, we need to start using it next time the user tries to add an event. So now we need to change the new action in the events controller, to make it instantiate the @event variable from the session, if there s any data in the session. To achieve this, we only need to call session[:event_draft]. Change the new action in the events controller as shown in Listing 7-14.
Listing 7-14. Updating the new Action in app/controllers/events_controller.rb
def new @event = session[:event_draft] || current_user.events.build end
We re almost finished. The only remaining issue is that after we create an event, we no longer want the application to remember what the draft event looked like; otherwise, the user will get the impression that the changes weren t saved. To prevent this, we just need to make sure that the Event object in the session in cleaned up after we save it to the database. All we need to do is make a small change to the create action to set the event_draft session to nil, as shown in bold in Listing 7-15.
Listing 7-15. Updating the create Action in app/controllers/events_controller.rb
def create @event = current_user.events.build(params[:event]) @event.categories << Category.find(params[:categories]) unless params[:categories].blank @event.tag_with(params[:tags]) if params[:tags] if @event.save flash[:notice] = 'Event was successfully created.' session[:event_draft] = nil redirect_to :action => 'index' else
CHAPTER 7 IMPROVING INTERACTION WITH AJAX
render :action => 'new' end end
To test this, run the application and start trying to create an event. Then navigate away. To your delight, you ll see that clicking the New Event link will take you back to the event form, which will still have the information you typed earlier. This is a feature your users will love to see in forms where a lot of data is entered.
Copyright © OnBarcode.com . All rights reserved.