how to get several same object values in a Grails form

Question

let's take a simpe domain class:

class Person { String aname }

A gsp form to let the user input a person is easy:

<g:form ...>
...
  someone:<input name="aname">
...
</g:form>

... and back in the controller, to get the values, I can just write

def p = new Person(params)

Now, I'd like to let the user input the data for two persons (let's say, two parents) in the same form. How to write this ? I just can't give the same name for the two input fields, but if I don't keep the original property name ("aname"), back in the controller I will have to handle by hand the bindings between the name of the property, and the form input names:

<g:form ...>
...
  father:<input name="aname1">
  mother:<input name="aname2">
...
</g:form>

then, in controller

def p1 = new Person(); p1.aname = params.aname1
def p2 = new Person(); p2.aname = params.aname2

Is there a way to keep the automatic binding facility even if there is several objects of same types given in a form ?

score 1 · Accepted Answer · answered May 06 '13 at 14:51

1

Try to use this way:

<g:form ...>
...
  father:<input name="father.aname">
  mother:<input name="mother.aname">
...
</g:form>

And controller:

def p1 = new Person(params.father); 
def p2 = new Person(params.mother);

answered May 06 '13 at 14:51

Mr. Cat

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Thanks Mr Cat, this dot notation is what I was looking for ... at least for the basic tag. Sadly, it does not work within fields plugin: I can write , but in that case, the returned param will by "name", and not "mother.name". And there is no way to write . Let's stay with tag, then. – Fred B. May 07 '13 at 09:43
have you tried to set ? – Mr. Cat May 07 '13 at 09:57
no, adding a "name" attribute does nothing more, but i discovered another "prefix" one that does the jobb. I explain this below, as an anwser (rather than an unformatted comment). – Fred B. May 07 '13 at 11:55

score 0 · Answer 2 · answered May 06 '13 at 14:17

I suppose you are thinking of doing something like this:

<g:form ...>
...
  father:<input name="aname">
  mother:<input name="aname">
...
</g:form>

which would result as ?aname=Dad&aname=Mom

You can handle them in controller as below:

params.list('aname').each{eachName -> //Persist each `aname`}

Have a look at Handling Multi Parameters.

score 0 · Answer 3 · answered May 07 '13 at 12:11

the dot notation in the "name" attribute works well for the <input> tag.

To go further, there is also a solution for the "fields" plugin: rather than using the "name" attribute, one should use the "prefix" one, as described here.

For example:

<f:field bean="mother" property="forename" prefix="mother."/>
<f:field bean="mother" property="surname"  prefix="mother."/>
<f:field bean="father" property="forename" prefix="father."/>
<f:field bean="father" property="surname"  prefix="father."/>

we can even write it better, with help of <f:with> tag:

<f:with bean="mother"  prefix="mother.">
   <f:field property="forename"/>
   <f:field property="surname"/>
</f:with>
<f:with bean="father"  prefix="father.">
   <f:field property="forename"/>
   <f:field property="surname"/>
</f:with>

how to get several same object values in a Grails form

3 Answers3