wpmem_mc_merge

Hi Mike – that’s an interesting question. I think you could do it with a logical test in your function – something like this:

add_filter( 'wpmem_mc_merge', 'my_mc_merge_filter' );
function my_mc_merge_filter( $merge_vars )
{
	if( $_POST['your-subscription-field'] == 'some-value' ) {
		$my_new_field = array(
			'MC_MERGE_FIELD_1' => $_POST['option-name-1'],
			'MC_MERGE_FIELD_2' => $_POST['option-name-2']
		);
	} else {
		$my_new_field = array(
			'MC_MERGE_FIELD_3' => $_POST['option-name-3'],
			'MC_MERGE_FIELD_4' => $_POST['option-name-4']
		);
	}
	$my_new_merge = array_merge( $merge_vars, $my_new_field );
	return $my_new_merge;
}

For anyone reading this later, there was an email conversation to this as well that was not part of the forum. To fill in that gap, the mail merge field was a radio group (radio groups only allow one of several selections) and of course the multiple select checkbox group allows multiple selections.

To discuss this, I’ll be using the the cookie group example from the multiple selection checkbox tutorial), the checkbox labels are Chocolate Chip, Oatmeal, Macaroon, and Peanut Butter. The checked values are chocolatechip, oatmeal, macaroon, and peanutbutter. For testing with the MC mail merge, I set up a field at MC “FAVCOOKIE” with the values being the same as the checkbox field labels.

The likely reason that the merge was failing is that if you set up the merge value the same as the others directly using the $_POST value ( ‘FAVCOOKIE’ => $_POST[‘fav_cookie’] ). The posted value is an array, even if the user selects only one checkbox. But the merge field is looking for a single string to match one of the possible values. So even if the MC radio group values were the same as the checkbox values (not labels), you couldn’t directly merge the two as they are different types (one is an array, one is a string).

One possible approach to this dilemma (and probably the easiest solution) is to make the MailChimp field a text field and then implode the checkbox selections to a comma separated string. Assuming still the cookie example, here is a merge taking the “fav_cookie” checkboxes, imploding them into a comma separated string, and passing them to merge with FAVCOOKIE which would need to be a text field at MailChimp:

add_filter( 'wpmem_mc_merge', 'my_mc_merge_filter' );

function my_mc_merge_filter( $merge_vars ) {

	// get the cookie checkboxes, make them a string for merging
	$cookie = ( isset( $_POST['fav_cookie'] ) ) ? implode( ",", $_POST['fav_cookie'] ) : '';
	
	// repeat for any additional checkbox groups...
	
	// the merge array with the $cookie value merging to FAVCOOKIE
	// (assumes FAVCOOKIE is a text value at MailChimp)
	// (repeat that concept for any additional checkbox groups
	$my_new_field = array(
		'FNAME' => $_POST['first_name'],
		'LNAME' => $_POST['last_name'],
		'FAVCOOKIE' => $cookie,
	);
	
	$my_new_merge = array_merge( $merge_vars, $my_new_field );
	
	return $my_new_merge;
}

Using everything as-is in the example, you will end up with a comma separated string of values at MailChimp that uses the “checked value” of the checkboxes (i.e. “chocolatechip,peanutbutter”). If you want those more ‘readable’ you can make the checked value of the checkboxes like “chocolate chip”.

Another possibility if you are going to use the radio button group at MC is to work with the checkboxes to set up something that will merge with the MC field.

To do that has a trade-off with the previous example. You get to keep the radio group at MC, but it can only have one value. So my example looks through the checked values and the first time it gets a match, it makes that the merge value and quits checking for more.

This example assumes that your MC radio group has the values “Chocolate Chip”, “Oatmeal”, “Macaroon”, and “Peanut Buttler”. The “case” values are the checkbox checked values used in the example snippet (same as before).

function my_mc_merge_filter( $merge_vars ) {

	$fav_cookie = $_POST['fav_cookie'];
	
	foreach( $fav_cookie as $cookie ) {
		
		$cookie_merge = '';
		
		switch( $cookie ) {
			case: 'chocolatechip':
				$cookie_merge = 'Chocolate Chip';
				break;
			case: 'oatmeal':
				$cookie_merge = 'Oatmeal';
				break;
			case: 'macaroon':
				$cookie_merge = 'Macaroon';
				break;
			case: 'peanutbutter':
				$cookie_merge = 'Peanut Butter';
				break;
		}
	
		// if we have a value, quit the loop
		if( $cookie_merge ) {
			break;
		}
	}
	
	// repeat for any additional checkbox groups...
	
	// the merge array with the $cookie value merging to FAVCOOKIE
	// (assumes FAVCOOKIE is a radio group at MailChimp)
	$my_new_field = array(
		'FNAME' => $_POST['first_name'],
		'LNAME' => $_POST['last_name'],
		'FAVCOOKIE' => $cookie_merge,
	);
	
	$my_new_merge = array_merge( $merge_vars, $my_new_field );
	
	return $my_new_merge;
}

I know that’s a lot to digest. Hopefully it makes some sense.

@bookpraiser – if your situation is matching up a radio group, you can see the explanation here. If it is anything else, we’ll need to look at what might be failing.

Regardless of if it is the same issue, though, you should still take a look at that explanation because are other field types – it could be a field type issue since the example given in the documentation is dealing with text fields.