Add custom capabilities by getting a drop down value

I am trying to add custom capabilities to user according to a value submitted from gravity form selected value.

I have tried gfrom_pre_render and gform_after_submission without any success.

Here is an example that I tried.

add_action("gform_after_submission_1", "after_submission", 10, 2);

function after_submission($entry, $form){
     $user = wp_get_current_user();
     $capabilities = $entry["17"] . ', '. $entry["18"] .', '. $entry["19"];

if ($capabilities = "1") {$user -> add_cap('1');}
if ($capabilities = "2") {$user -> add_cap('2');}
if ($capabilities = "3") {$user -> add_cap('3');}
}

It seems the code above add all values that field ID 17, 18, 19 has to user capabilities.

So I tried another with gform_pre_render

'
add_filter("gform_pre_render", "dropdown_custom_capabilities");
add_filter("gform_admin_pre_render", "dropdown_custom_capabilities");
function dropdown_custom_capabilities($form){
if($form["id"] != 1)

return $form;

$terms = get_terms("custom-capabilities");
$items = array();
$items[] = array( "text" => __('Select capabilities...', "value" => 0 );

foreach($terms as $term)
$items[] = array( "text" => $term->name, "value" => $term->slug );

foreach($form["fields"] as &$field)

if($field["id"] == 17 OR 18 OR 19){

$field["cssClass"] = 'custom-capabilities';
$field["choices"] = $items;
}

return $form

if ($form = "1") {$user -> add_cap('1');}
if ($form = "2") {$user -> add_cap('2');}
if ($form = "3") {$user -> add_cap('3');}

}

'

Code above does not work.

Would you possibly to point me a right direction for this matter?

Thank you for reply!
I guess I need to make it simple.

Let's assume that field ID 17 of Form ID 1 has dropdown values such as "A", "B" and "C"
and we modified code on line 5 to $capabilities = $entry['17];

With this $capabilities contain all dropdown values of Field ID 17 of Form ID 1, which are "A", "B" and "C", thus add custom capabilities "a", "b" and "c" to the current user.

What I would like to know is to add only "B", if a user selected "B"

I have somehow managed to have it work. So blind I was unable to recognise a solution right in front of myself.

Here is my code:

[php]
add_action('gform_after_submission_(your form ID)', 'add_new_capabilities', 10, 2);
function add_new_capabilities($entry, $form){

$current_user = wp_get_current_user();
        $custom_cap1 = $entry["(field_ID)"];
	$custom_cap2 = $entry["(field_ID)"];

$current_user -> add_cap($custom_cap1);
$current_user -> add_cap($custom_cap2);
}

This code will add data to your datatable wp_usermeta - wp_capabilities without any arraying problem.

As for the code I referred previously, It seems $entry returns all values contained in the dropdown as it is used in 'if phrase.' I don't know why.

Any simplification and suggestion are more than welcomed.