Dropdown Field

gistfile1.php

<?php

		$blob = new DropdownField(
			'EmployeeOfTheMonthID',
			'Employee of the month',
			 $this
			 	->Children()
			 	->filter('ClassName', 'StaffPage')
			 	->sort('Title')
			 	->map('ID', 'Title')
		);
		$blob->setEmptyString('(Select)');

		$fields->addFieldToTab(
			'Root.Main',
			$blob,
			'Content'
		);