The dropdown in my form is only submitting the ID (ie 4) instead of the value (ie Atlanta, Georgia 323 S. 2nd St.). In the $source, I tried switching out "ID" with "LocationDropDown" but that resulted in no data in the dropdown on the site.

Do I need something else to process the form instead of $data['StoreLocale']?

StoreLocation.php

class StoreLocation extends DataObject {
	
    public static $db = array(
		'Address' => 'Varchar(80)',
		'City' => 'Varchar',
		'State' => 'Enum("-- Select a state --,Alabama,...,Wyoming")',
	);
	
	// Populate Dropdown on Contact Form
	function LocationDropDown() {
		 return $this->City . ', '. $this->State . ' - '. $this->Address;
	}

}

ContactPage.php

class ContactPage_Controller extends Page_Controller {

	// CONTACT FORM

	function ContactForm() {
		// Create fields
		$fields = new FieldSet(
			...
			new DropdownField(
			    $name = 'StoreLocale',
			    $title = 'If your comments pertain to a specific store, please pick a location',
			    $source = Dataobject::get("StoreLocation")->map("ID", "LocationDropDown", $emptyString = "-- Select Location --", $sortByTitle = false),  
			    $value = 0
			),
                        ...
		);
	
		// Create actions
		$actions = new FieldSet(
		   new FormAction('doContactForm', 'Submit Form')
		);

		$validator = new RequiredFields("Email","Comments");
		return new Form($this, 'ContactForm', $fields, $actions, $validator);
	
	}
	
	// PROCESS THE FORM
	function doContactForm($data, $form) {
		
		//Set data
                ... 
		$body = '<h1>Feedback / Comments</h1><p><b>From:</b> '.$data['Email'].'</p>'.'<p><b>Location:</b> '.$data['StoreLocale'].'</p>'.$data['Comments'];
		$email = new Email($from, $to, $subject, $body);
		$email->send();
	}
}

Thanks

This is how DropdownFields work. If you want the returned data to be your 'LocationDropDown' field then simply map it to that instead of ID.

Dataobject::get("StoreLocation")->map("LocationDropDown", "LocationDropDown");

Usually an ID is much more useful as you can do a DataObject::get_by_id() in the process function and get the entire object rather than just a string but in your case it would work either way since all you want is the 1 address.

Will's code won't work due to the way the map() function makes it indexes.

$values = Dataobject::get("StoreLocation")->column('LocationDropDown');
...
new DropdownField(
'StoreLocale',
'If your comments pertain to a specific store, please pick a location'
array_combine($values, $values),
null,
null,
'-- Select Location --'
)
...

@Willr
If I was just grabbing the City or State or Address (ie "Address", "Address") that would have worked. But since I had the LocationDropDown() to concatenate the city, state - address, replacing the "ID" broke the form.

@simon_w
That solution worked for me :-)

Thank you both!