I need to display dynamical charts based on user's choises.
I want to let the user choose options from several select menus filled by data coming from db tables.
When the user submit the page, I want to fire a query in order to get the data to build my charts with.
I'm new to Rails and I cannot figure out how to do this.
I've made a new model, setting it to "Abstract" (as I don't need to write anything to the db, just display query results) but I don't know which action I have to use (index, new etc.).
I hope I had correctly explained the problem.
Thank you
Looking at your problem in your views you can use form_tag with remote: true option and url set to your index action. Add your business logic to return chart data in index action. remote: true option will fire request asynchronously. In your views use returned data to display chart.
Related
In rails, I have a UserOffer model, that has_many Steps.
When I create a new UserOffer instance, I want that form to include a dropdown that says “select number of steps of that UserOffer”. Based on the number of steps selected (n), I want the form to expand, and include n extra fields, called “step 1 title”, “step 2 title” … “step n title”.
I figured I need to use nested attributed to do this, but I wanted to know how the form would look like, preferably without using JS or Ajax (just with RoR).
I would appreciate any help
If you want to do that, at the same form without refreshing the page, you will need to use an ajax request to the server, in order to add the steps to the UserOffer model. Remember that RoR only let you do things on the render step of the DOM, in other words, if you had rendered the form you will not be able to do another changes on the page without use javascript.
I am trying to create a page that shows a table that contains products and I would like for the user to be able to toggle the categories. For example, if there are categories jeans, shirts and jackets, I would like a set of checkboxes that would toggle between showing the three categories of products. The problem is that I am unsure of how to approach this problem. I am not sure how to allow the user to relay the information to the controller without changing every users toggled categories. I also don't know how to get around the fact that refreshing the page to refresh the table would simply reset all of the categories.
you can do it in this way,
based upon event click of checkbox fire up ajax request on get req/param_catagory
get and assign data and load it over data table
you can use jquery data table plugins for that
There are few easy jquery plugins for that example: jquery data table
Hope this will help.
I have a form with a country select. The form should be extended with new input fields depending on the selected country.
Most of the tutorials i found on google are for ajax submits after filling a forum.
Can somebody recommend a tutorial/howto on howto extend a form via ajax on a select change?
Use something like this. Of cousre url, country_data, and custom_part must be handled according your app. And the returned data comes from your app, better without layout, only the part what you want to add.
$.get("url", country_data, function(returned_data){ $(".custom_part").html(returned_data) })
Specifically, I have a number of pages in my Rails app that use the same partial. In the action handler for each page I create an array object (e.g. #list_elements) based on a database query. Each page uses a different query so that each page has different list elements in it. At the top of each page I have a form_remote_tag containing an edit field, allowing the user to add a new element in a dynamic, AJAXy fashion (think something like Twitter 'What's happening' box).
My problem is that when the AJAX command fires I need to reload the list to include the newly added item, but the contents of the list were determined by a database query. I need to remember which query applies to the current page (i.e. controller action) so that I can run it again. I thought about storing something in the rails session structure but it seems like overkill - it's like storing the current page all the time.
Anybody done anything like this and have a nice Railsy way to achieve it?
Ben
Couldn't you just re-render the partial in your rjs template?
page[:div_element].replace_html :partial => 'partial'
If you perform the query and define the array in the controller action, then an ajax call will refresh that array.
The best public example that I can think of off the top of my head would be the amazon shopping cart. Where you have a page that displays multiple distinct records that can have multiple distinct fields updated.
I can't put each one in a form tag because the user may modify more than one record and then submit.
I can't just update all the records that I get back because:
1. Performance
2. Auditing
3. If someone changed the record that the user 'didn't change' when they were viewing the page and then the user submits those changes would be overwritten.
So how to best handle getting the data back and then getting which records where changed out of that?
Is that clear?
Use binding! Don't be iterating the form collection in your actions.
Steve Sanderson wrote a blog post about how to do it. I wrote a blog post on how to do it with MvcContrib.FluentHtml. Both posts are very detailed and include downloadable code.
Generate your form in a repeater, and append an ID to the form elements that increments with each new form. Save the number of repeated form elements in a hidden field. Then in your controller, read the value of this hidden field - that'll be the number of forms to read. Then, in a loop, retrieve each form's fields by specifying the name of the field, plus the loop index appended to the name, as the key.
You can use some javascript logic to detect when a form's value changes, and update a hidden field in that form's section if that occurs; or you can hide the original values inside a hidden field with each form section (although I don't recommend this as too many fields / forms will bloat your page).
one (but not necessarily the best) approach is to store which items are changed in a js-variable or something on the client side as they are changed, and then only send the data that is actually different from what the user recieved.
and as Erik stated, you could use hidden form elements to make sure that it works without js as well.