grails: how to dynamically construct a form?

Question

I need to create a dynamic form in grails which has various dynamically created input boxes at runtime, which then submits its params to a controller just like a form created at compile time. Any ideas?

The view gsp might look like this:

<g:form controller="report" action="view">          
   <input type="submit" value="Submit">
   <!-- insert some inuput params here at runtime -->
</g:form>

and the action controller would be:

class ReportController {
def view = {
    def someDynamicParam = "someParam"
    if (params["someParam"] != null) {
       ...
    }

The problem is I have no idea how to render the form input fields in a way that grails will understand them on submission.

Run grails install-templates and have a look at the script which is used to generate scaffolding views. There may be a hint or two in there. — zoran119
where do you want the input fields created - at the client browser or at the server side? accordingly look at zoran119's comment or Sérgio 's answer respectively — aldrin

Unknown Unknown · Accepted Answer · 2014-03-05T01:13:49

To create dynamic input's you need JavaScript. I suggest you to use some framework to make it easier. Taking JQuery as example:

$('<input>').attr({
    type: 'text',
    id: 'foo',
    name: 'foo'
}).appendTo('form');

Then you need to think how to bind it to a Domain Class. Looking at your question I cannot see what you need, but let's make an example where the user can set values:

//domain class
class MyDomainClass {
  String value
}

//javascript to add a new value
$('<input>').attr({
    type: 'text',
    name: 'values'
}).appendTo('form');

//controller submit action
class MyController {
  def save() {
    def values = params.list('values') //get the list of values
    values.each {
      MyDomain instance = new MyDomain(value: it)
      instance.save()
    }
  }
}

The key here is to use the same name in your html, and to use params.list() to transform the submited values in a List.

grails: how to dynamically construct a form?

2 Answers