Change Custom Field / Multi-Select output (to work with Advanced Custom Fields)

Hello,
I am working on a project which uses Gravity Forms (GF) as the frontend UI and Custom Post Types enhanced by Advanced Custom Fields (ACF) to manage data backend.
All is working very good but 1 thing, when dealing with multi-selection.

Here are the differences between GF & ACF :
- GF stores multi-selection as many custom meta fields with the same meta name.
- ACF stores multi-selection as a single custom meta, with its data separated by a comma.
Therefore, they can match together.

Could it be possible to have GF working the same way ACF is when using Custom Fields ?
Or maybe you could tell me where I could make a hack into GF code (not very recommended though) or maybe a new filter ?

Best regards,
Antoine
Antoine

Nope ; not solved.

if i look in the backend form and the notification email then i found the expected result.

a:2:{i:0;s:4:"ipad";i:1;s:6:"iphone";}

Why modify gravity form a serialized string again?

Sorry for my bad english. It seems you don't understand my Problem.

If i chose checkboxes the gravity forms stores (if 2 checkboxes checked) the value like
name_of_field value_1
name_of_field value_2

2 rows

That is not nice but as david told i can fix it with gform_pre_submission_filter. Look at my code above - i did it allready! I create allready the wanted value (a:2:{i:0;s:4:"ipad";i:1;s:6:"iphone";} ) and in the mail i see that value (trailing after a dot).

But when i look in the database, then i found a
s:35:"a:2:{i:0;s:4:"ipad";i:1;s:6:"iphone";}";

That is the serialized value of my wanted result. I don't understand why gravity form serialize that again!? If gravity form want a serialzied value, then why saving 2 rows? My data is perfectly in line 7 on my example above - but stored is another value

HI, in your example (GForm_post_data) i only see the possibility to change standard post fields. But in my case i have a custom field to manipulate.

okay ... i found a solution without any hooks or filters but the solution isn't nice because i can't upgrade the plugin

i modify your forms_model.php (line 1745 and more)

case "checkbox" :
                        $value = explode(",", $value);
						$arr = array();
                        if(is_array($value)){
                            foreach($value as $item){
                                if(!rgblank($item))
                                    $arr[]=$item;
                            }
							add_post_meta($post_id, $meta_name, $arr);
                        }
                    break;

is their a way to put the code on a other place?

Btw. my solution gives a clean output in the backend and works with all my other plugins and templates