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.
Related
In my project, an Article has many Items within it. Since each Item has different length, so I would like to implement pagination manually, for example, by creating a PageBreakItem model, in order to allow users insert page breaks wherever they want. But I don't know how to use "page" parameter in controller to render views correctly.
Some gems like kaminari or will_paginate only allow me to configure the number of items per page. They don't have options for inserting page breaks manually.
Any suggestions are greatly appreciated.
You don't need a special model for this. You could do this with small adaptation of your Item model:
Add sort_order numeric field to denote order of items within the article and is_on_new_page boolean field to denote a page break occurring before that article.
I want to create several instances of same model form a single form. And more importantly, the number of instances aren't known before form rendering.
I've seen several tutorials of this kind, but unfortunately those didn't suit my need. I've seen Ryan bate's nested form tutorial. But I'm not creating nested form. I've also seen some tutorials, which do create multiple objects, but the number of object's are all known in those cases. One of the tutorial is here - http://archive.railsforum.com/viewtopic.php?id=717
User will click a button and a new set of fields for a new object will be inserted just like the nested form demo from ryanb.
Here is a mockup of what I want. It's basically a very small form fit into a single line.
As i understand you need cocoon gem it allows to add form fields
It sounds like you may need to reach beyond Rails views and utilize javascript to dynamically render more "partials" when the user decides to add more fields. Something like this: Adding input elements dynamically to form
If you want to keep your view rendering logic in rails, you could make an AJAX request to your application, have it return just a partial's worth of html back, and insert the response html into your dom.
I'm trying to set a set of fields to be dynamically displayed on demand. In the model, I've the fields:
attr_accessible ... :instruct1, :instruct2, ... :instruct30
I would like the form to display just instruct1 with a button to add 1 more field until instruct30 is hit and a button to remove one until instruct 1 is hit. All should happen without refreshing page which i think would include some use of AJAX but I couldn't find anything that is similar.
I've searched for something similar but only able to come up with nested form which is not what im looking for as my model is fixed.
The majority of your work is going to be on the client side.
To add and remove form fields dynamically, you have to use javascript.
Check out the HTML that Rails generates for the first field, replicate that and add the additional fields using for example jQuery.
A crude example:
$("#button").click(function() {
$("#theForm")
.append('<input id="instruct2" name="object[instruct2]" type="text">');
});
You'd have to keep track of how many fields you've added or removed.
Before starting, I do have a very particular question and if you want to answer it go straight to the end. But I do welcome comments and advices hence the lengthy post.
OK, we deal with a lot of forms and some of these forms are quite lengthy and have many fields. We also have a requirement - in addition to top level fields - to be able to have variable number of repating rows - as we call them. For example, let's think of a customer which has name, surname and age while it can have zero or many addresses (say 0 to 10) so the user must be able to add or remove contacts from the form while filling it in. So typically user gets and "Add" button to add more addresses and next to each address, a delete button. Potentially there could be more than one repeating section in the same form but I am not going there. The point is, because of legal and historical reasons, all the forms must be saved at once so while the forms can be edited, we cannot accept a half-filled form and have another page for users to add and remove addresses, e.g.
I am using ASP NET MVC 2 (strongly typed views with a single generic controller) with client side validation and heavy jquery scripting for flashy features. We are probably going to migrate to ASP NET MVC 3 very soon and I am already playing with 3 for finding a good solution. These addresses are defined on the Model as List<Address>, e.g.
I currently have a working solution for this issue but I am not satisfied with it: I have an HTML Helper that names the add or delete buttons and a bit of JavaScript to disable validation and allow the form to be posted back (even invalid) and since I can find out the name of the button that was clicked, I have all the necessary logic to handle add or delete and works really well.
But I am posting back and the form is reloaded and I am looking for an aletrnative solution. Here are what I can do:
Do everything in the client side. "Add" button will clone one of such addresses and "Delete" button will remove() the element. I only have to rename the indexes which I have done. We were using jquery calendar and it was breaking on the new elements which I have also fixed. But the validation is not working which can probably work with ASP NET MVC but this solution looks like a very brittle one - a house of card which looks great before you add another card.
Post the whole page usin Ajax and then load it back again: This is probably better than my current solution but only slightly.
Use ajax to post the form and get back JSON and use the data to build the elements or remove them: Again a house of card because of extensive client side scripting
Serialize the form and post using Ajax to a particular action and get back only the repating section (as a partial view). The action on the controller can be reused and called from the view itself to return the partial view
OK last one is the one I am working on but there is an issue. ASP NET MVC 3 with unobtrusive validation works only if the form is engulfed in a BeginForm() while my top level view has a BeginForm() but not my partial view. It works well when I call it from the view but not on the ajax call to get just the repeating section.
(Question)
So is there a way to tell ASP NET MVC 3 to spit out validation data atttributes regardless being in a BeginForm() block?? To be honest if this is not a bug, this is definitely an important feature request. I have in fact used reflector to disassemble the code and the condition seems to be there.
Short Answer:
Add this to the partial view:
if (ViewContext.FormContext == null)
{
ViewContext.FormContext = new FormContext();
}
I don't think it is possible using the default unobtrusive libraries supplied. If you look at jquery.validate.js and jquery.validate.unobtrusive.js it looks like it only validates what is inside the form.
There's a few posts about it if Googled and a few work arounds.
I had a similar issue (although much simpler) where I had a validation summary at the top of the page and multiple forms but the unobtrusive javascript would only populate the view summary if its inside the form (jquery.validate.unobtrusive.js line 39 if interested...).
I'm not sure if the validation library is extendible but most things in jquery are so that might be an option if you want to go down that road.
As far a possible solution to your problem I'll put in my 2 cents for whats its worth.
You could have two actions that are posted to. The first action is you post your model with no js validation and all validation is handled in the code - this will catch all user with javascript turned off.
Your second action is you serialized the model. In mvc 3 using the Ajax.BeginForm has an AjaxOption for Url where you can specify an action for the jquery to call (where it serializes the form form you and you can decorate your action with your strongly typed model). Here you can check the model and return a json result and handle this in the javascript.
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.