title: SilverStripe MultiSelectField selected array
body: <p>I've been using the wonderful MultiSelectField add-on <a href="http://addons.silverstripe.org/add-ons/fullscreeninteractive/silverstripe-multiselectfield" rel="nofollow">http://addons.silverstripe.org/add-ons/fullscreeninteractive/silverstripe-multiselectfield</a> on a front-end form.</p>
  
  <p>This form is used to edit entries that have already been added via another form. The issue I'm having is that when retrieving an array ($FeedbackCategorySelected) to populate the field with previous selection(s) it doesn't seem to take the argument. For instance if the array was (1,3) it will only display the record for 1 and not 3.</p>
  
  <p>As this field is extending the CheckboxFieldSet I would have assumed it would work in exactly the same way.</p>
  
  <p>Can anyone shed any light on what could be wrong here? Code below.</p>
  
  <p>Many thanks</p>
  
  <pre><code>...
  $urlID = $this-&gt;request-&gt;param('ID');
  if(is_numeric($urlID)){
      $CallEvent = DataObject::get_by_id("CallEvent", Convert::raw2sql($this-&gt;request-&gt;param('ID')));
      $Feedback = DataObject::get_by_id("Feedback", $CallEvent-&gt;FeedbackID);
      $FeedbackCategorySelected = $Feedback-&gt;FeedbackCategories;
      $FeedbackCategory = FeedbackCategoryData::get()-&gt;map('ID', 'Title')-&gt;toArray();
  }
  ...
  $fields = new FieldList(
  new MultiSelectField(
      'FeedbackCategories',
      'Select feedback categories to add or remove',
      $FeedbackCategory,
      $FeedbackCategorySelected
  )
  ...
  </code></pre>