how to bind list of ids to command object in grails?

Question

Let's say when you submit a form it sends a list of ids.

<form action="/process">
<input type="hidden" name="ids" value="4, 6, 10, 14, 20, 56" >
<input type="submit" value="Submit">
</form>

At the controller side

def process(EmailCommand cmd){

   //now iterating over registrations after data binding
   cmd.ids.each {

    }
}


//Command Object
class EmailCommand {
  List<Registration> ids
}

I want to bind all the ids passed to controller to the ids list in EmailCommand command object. How can i achieve it? I appreciate any help! Thanks!

Answer 1

You have 2 options here:

Straight forward -> trick with the split comma-separated String in the "setter":

class EmailCommand {
  List<Registration> ids
  void setIds( String val ){ ids = Registration.getAll( val.split( ', ' ) ) }
}

Correct -> use form params for that:

<form action="/process">

<g:each in="[4, 6, 10, 14, 20, 56]" var="id">
  <input type="hidden" name="ids" value="${id}" >
</g:each>
<input type="submit" value="Submit">
</form>

and let grails do the binding.

Answer 2

I could only get it to work after changing the command object to

class EmailCommand{

    List<Registration> ids=  ListUtils.lazyList([], { new Registration() } as Factory )

}

and view to the following as bassmartin suggested.

<g:hiddenField name="ids[0].id" value="1"></g:hiddenField>
<g:hiddenField name="ids[1].id" value="2"></g:hiddenField>
<g:hiddenField name="ids[2].id" value="3"></g:hiddenField>
<g:hiddenField name="ids[3].id" value="4"></g:hiddenField>
<g:hiddenField name="ids[4].id" value="5"></g:hiddenField>


<g:submitButton name="submit" value="submit"></g:submitButton>

I am wondering why empty list in command object doesn't work. Is this limitation of grails version 2.2?

Answer 3

It would be something like

<form action="/process">
    <input type="hidden" name="ids[0].id" value="4" >
    <input type="hidden" name="ids[1].id" value="6" >
    <input type="hidden" name="ids[2].id" value="10" >
    <input type="hidden" name="ids[3].id" value="14" >
    <input type="hidden" name="ids[4].id" value="20" >
    <input type="hidden" name="ids[5].id" value="56" >
    <input type="submit" value="Submit">
</form>

Or if you want something more dynamic :

<form action="/process">
    <g:each in="[4, 6, 10, 14, 20, 56]" var="id" status="i">
        <input type="hidden" name="ids[${i}]" value="${id}" >
    </g:each>
    <input type="submit" value="Submit">
</form>