Handling form with repeatable inputs - grails

Question

Before i start with my question, i will try to explain on what i'm trying to do.
I'm creating a form using Grails, and in the form, there are 2 sections on it, the primary input and the repeatable input. See below for ideas on how the structure looks like.
<div class="primary">
<div class="${hasErrors(bean: dataInputInstance, field: 'mainInput', 'error')}">
<label class="control-label">
<g:message code="dataInput.mainInput.label" default="Main Input"/>
</label>
<div class="controls">
<g:textField name="mainInput" value="${dataInputInstance?.mainInput}" />
</div>
</div>
</div>
<div class="repeatable">
<div class="span6">
<div class="${hasErrors(bean: dataInputInstance, field: 'inputA', 'error')}">
<label class="control-label">
<g:message code="dataInput.InputA.label" default="Input A"/>
</label>
<div class="controls">
<g:textField id='inputA_1' name="inputA" value="${dataInputInstance?.inputA}" />
</div>
</div>
</div>
<div class="span6">
<div class="${hasErrors(bean: dataInputInstance, field: 'inputB', 'error')}">
<label class="control-label">
<g:message code="dataInput.InputB.label" default="Input B"/>
</label>
<div class="controls">
<g:textField id='inputB_1' name="inputB" value="${dataInputInstance?.inputB}" />
</div>
</div>
</div>
The repeatable part of the input can be repeated from 1-50 times. The number of instances generated and saved in the database depends on how many repeated form created. Each instance is a combination of primary input + repeated input.
If say, i created 5 repeated sections, then when saving the form, the params will look like below
params:[mainInput: valMain, inputA:[valA1, valA2, valA3, valA4, valA5], inputB :[valB1, valB2, valB3, valB4, valB5]]
In the controller, i used the following when i try to form the instances and save it to the database
def save() {
def length = inputA.size()
def i
if (i = 0; i < length; i++){
DataInput dataInputInstance = new DataInput()
dataInputInstance.mainInput = params.mainInput.trim()
dataInputInstance.inputA = params.inputA[i].trim()
dataInputInstance.inputB = params.inputB[i].trim()
dataInputInstance.save(flush:true)
}
}
So far i managed to get that part correct.
Now here comes the problem.
Inside the save controller, i plan to include some data checking before i save it to the database. If checking is success, then it will proceed to save the data. If its not, then it will return back to the form page, together with the data that user input in the form. The code for that is as follow
if (insert checking condition here){
render(view: "create", model: [dataInputInstance: dataInputInstance]) //If fail
}
If the amount of repeatable part is 1, then the form will render along with the data that the user input. However if the repeatable part is more than 1, then it will have trouble to pass the data back to the form.
I tried to pass back the params back to the form because i thought since the params contain arrays on it, so it would be logical to pass back the params to the form, like below
if (insert checking condition here){
render(view: "create", model: [dataInputInstance: params]) //If fail
}
But still not working.
So anyone have any idea on this?

Answer 1

I'm looking at this block where you are setting dataInputInstance.inputA to be a single value and not the entire list object. Is this what you intended?
dataInputInstance.inputA = params.inputA[i].trim()
dataInputInstance.inputB = params.inputB[i].trim()
Could you post your view GSP code if this is not the cause? Need to see how are you reading the values from your view on validation failure.