Hey Guys

I have extended the Event Calendar in similar ways to the recipe in the docs http://doc.silverstripe.org/doku.php?id=recipes:extending_the_event_calendar but I'm having an issue adding an extra Filter Dropdown field (under the Calendar Widget) and getting it to work.

Basically, in the context of the tutorial/recipe I linked to, I want to be able to filter by Instructor.

That is, I have a many_many relationship between CalendarDateTime.php and Instructor.php and I would like to add a drop down field of Instructors under the existing From and To Calendar Filter dropdowns.

I got to here:

	public function getFilterFields() {
		$fields = parent::getFilterFields(); // returns a CalendarFilterFieldSet
		$instructors = DataObject::get('Instructor');
		$map = $instructors ? $instructors->toDropdownMap('ID','Name') : array();
		$fields->addFilterField(new DropdownField('CalendarDateTime_Instructors','Instructor', $map));
		return $fields;
	}

but as I expected it's looking in the db for an "Instructors" column in the CalendarDateTime table (which it doesn't find and so errors) rather than matching it up via a joint CalendarDateTime_Instructors table.

Is what I'm trying to do possible?

Sorry, it's a one-to-one filter at the moment. If you want to try to modify the filter functionality to support many_many or has_many, that would be awesome. I imagine it's a lot of work, especially to do it cleanly.

Ultimately, I think we just need to have the ability to hand off the filtering to a custom callback function.

Yeah fair enough. I think might be a little beyond me, time-wise but also mad-skillz-wise atm lol. If I do end up tweaking I'll post what I come up with here. Any starting points/suggestions?

It's a little sloppy but you can get a many_many join going by overriding 3 Calendar methods: Events, getEventJoin, and getDateJoin

Here's a quick example...

	public function getEventJoin() {
		$join = parent::getEventJoin();
		
		if (isset($_GET['center']) && is_numeric($_GET['center']) && (int)$_GET['center'] > 0) {
			$center = (int)$_GET['center'];
			$join .= " LEFT JOIN `EventDateTime_Centers` ON `EventDateTime_Centers`.`EventDateTimeID` = `EventDateTime`.`ID`";
		}
		
		return $join;
	}
	
	public function getDateJoin() {
		$join = parent::getDateJoin();
		
		if (isset($_GET['center']) && is_numeric($_GET['center']) && (int)$_GET['center'] > 0) {
			$center = (int)$_GET['center'];
			$join .= " LEFT JOIN `EventDateTime_Centers` ON `EventDateTime_Centers`.`EventDateTimeID` = `EventDateTime`.`ID`";
		}
		
		return $join;
	}

	public function Events($filter = null, $start_date = null, $end_date = null, $default_view = false, $limit = null, $announcement_filter = null) {
		if (isset($_GET['center']) && is_numeric($_GET['center']) && (int)$_GET['center'] > 0) {
			$center = (int)$_GET['center'];

			if ($filter) {
				$filter .= ' AND ';
			}
			$filter .= "`EventDateTime_Centers`.`CenterPageID` = '$center'";
		}
		
		return parent::Events($filter, $start_date, $end_date, $default_view, $limit, $announcement_filter);
	}