Multiple rows with same ID in Silverstripe GridField - silverstripe

Question

is there a way to group a GridField (for example, by ID)? The following Query (many_many) returns some dataobjects twice or more, if they havent the same SortOrder. Here is some code. I hope that somebody can help ;-)
private static $many_many = array(
'Mitarbeiter' => 'Mitarbeiter',
);
private static $many_many_extraFields = array(
'Mitarbeiter' => array(
'SortOrder' => "Int"
)
)
// Start Mitarbeiterzuordnung
$MitarbeiterFieldConfig = GridFieldConfig::create()->addComponents(
new GridFieldToolbarHeader(),
//new GridFieldSortableHeader(),
new GridFieldDataColumns(),
new GridFieldDeleteAction('unlinkrelation'),
new GridFieldSortableRows('SortOrder'),
new GridFieldManyRelationHandler(), 'GridFieldPaginator',
new GridFieldPaginator(20)
);
$MitarbeiterField = new GridField("Mitarbeiter", "Mitarbeiter", $this->Mitarbeiter()->sort('SortOrder'), $MitarbeiterFieldConfig);
$fields->addFieldToTab('Root.Mitarbeiter', $MitarbeiterField);

Answer 1

There is an issue with GridFieldManyRelationHandler.php and having a private static $many_many_extraFields as sorting field.
The query runs with the SortOrder being different and because it uses distinct, the ones having a different values are seen as extra, this is why the ones that have an order set show up twice.
You need to create a copy of GridFieldManyRelationHandler.php (I called it GridFieldManyManyRelationHandler.php) and edit the following function:
public function getManipulatedData(GridField $gridField, SS_List $list) {
if(!$list instanceof RelationList) {
user_error('GridFieldManyRelationHandler requires the GridField to have a RelationList. Got a ' . get_class($list) . ' instead.', E_USER_WARNING);
}
$state = $this->getState($gridField);
// We don't use setupState() as we need the list
if($state->FirstTime) {
$state->RelationVal = array_values($list->getIdList()) ?: array();
}
if(!$state->ShowingRelation && $this->useToggle) {
return $list;
}
$baseClass = $list->dataClass();
return $baseClass::get();
}
Then call that new class from your code, ie
private static $many_many = array(
'Mitarbeiter' => 'Mitarbeiter',
);
private static $many_many_extraFields = array(
'Mitarbeiter' => array(
'SortOrder' => "Int"
)
)
// Start Mitarbeiterzuordnung
$MitarbeiterFieldConfig = GridFieldConfig::create()->addComponents(
new GridFieldToolbarHeader(),
//new GridFieldSortableHeader(),
new GridFieldDataColumns(),
new GridFieldDeleteAction('unlinkrelation'),
new GridFieldSortableRows('SortOrder'),
new GridFieldManyManyRelationHandler(), 'GridFieldPaginator',
new GridFieldPaginator(20)
);
$MitarbeiterField = new GridField("Mitarbeiter", "Mitarbeiter", $this->Mitarbeiter()->sort('SortOrder'), $MitarbeiterFieldConfig);
$fields->addFieldToTab('Root.Mitarbeiter', $MitarbeiterField);
This probably should be refactored and the two classes should be separated (one class handling many_many and the other has_many).