how can I declare the sort and sort direction on the ModelAdmin results?

here is my code for the DataObject.

<?php
class Contact extends DataObject {
 
   static $db = array(
      'ContactNameFirst' => 'Varchar(100)',
      'ContactNameLast' => 'Varchar(100)',
	  'ContactPhoneHome' => 'Varchar(100)',
	  'ContactPhoneCell' => 'Varchar(100)',
	  'ContactEmail' => 'Varchar(200)',
      'ContactComment' => 'Text',
	  'Referrer' => 'Varchar(200)'
   );
 
   static $searchable_fields = array(
      'ContactNameFirst',
      'ContactNameLast' 
   );
   
     static $summary_fields = array(
      'ContactNameFirst',
      'ContactNameLast' 
   );

 
}
?>

For anyone with the same question, since i just needed a single field sort, I modified the sort setting for this table in MySQL and this seemed to suit my needs.

There's a DataObject::$default_sort property which gets applied whenever no sort parameter is explicitly passed. There's currently no way to specifiy this directly for ModelAdmin, but its on the cards for a more flexible tabular representation in the future.

ModelAdmin sure look promising ! It is pretty basic at this stage , but I can definitely see the potential , great work !

Does anyone know if there is a way I can use a custom build column sort in the model-admin list ?

You can use ModelAdmin::resultsTableClassName to customize the TableListField class being used for results. You can then create a subclass of it to provide custom functionality. If you just want different sorting, you can modify ModelAdmin->ResultsForm(), YourDataObject->getSearchContext(), or even just the default ordering through DataObject::$default_sort :)