Panels 3: Pane Visibility Rules (Evaluating $contexts Variable)

Last updated October 24, 2011. Created by steveoliver on October 24, 2011.
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Panel panes can be configured to appear when PHP code evaluates TRUE.

For example, a pane displaying the field(s) for a node may only make sense when that field actually has values.

Using the $contexts variable available to content pane visibility settings, one can evaluate such a condition in PHP.

1. Add a new rule
   
   
   
2. Inspect the $contexts variable

   While the PHP code must ultimately return a boolean value, temporarily output the contents of our $contexts variable using drupal_set_message():

   

   Visit your Panels page and you will see the output of the entire $contexts variable -- a variety of nested objects and arrays pertaining to the page.

3. Evaluate your condition(s)

   After finding the $contexts properties or element(s), return a boolean value (optionally using the negation (NOT) option instead of a PHP operator):

   

In this example, the panel pane will only appear when the specified condition is met--when the array defining the node's file_field property (array) is not empty.