Changing the collection in observer in Magento 1 issue

Question

I added a new column to my sales order grid and it works perfectly. If I go the the recent orders grid from the customer view it doesn't work . I got an error message: Column not found: 1054 Unknown column 'c.increment_id' in 'field list'.

This is how I added the new column to my sales order grid:

public function beforeBlockToHtml(Varien_Event_Observer $observer)
    {
        $grid = $observer->getBlock();
        /**
         * Mage_Adminhtml_Block_Sales_Order_Grid
         */
        if ($grid instanceof Mage_Adminhtml_Block_Sales_Order_Grid) {
            $grid->addColumnAfter(
                'customer_increment_id',
                [
                    'header' => Mage::helper('ffm_codebin')->__('Customer Inc.'),
                    'index'  => 'customer_increment_id',
                    'filter_index' => 'c.increment_id'
                ],
                'entity_id'
            );
        }
    }
public function beforeCollectionLoad(Varien_Event_Observer $observer)
    {
        $collection = $observer->getCollection();
        if(!isset($collection)){
            return;
        }
        if($collection instanceof Mage_Sales_Model_Resource_Order_Grid_Collection){

            $collection->getSelect()->join(['c' => $collection->getTable('customer/entity')]
                ,'main_table.customer_id = c.entity_id', ['customer_increment_id' => 'increment_id']
            );
        }
    }

These are the events which I used: core_block_abstract_to_html_before and core_collection_abstract_load_before. Please note that I do not want to add a new column for the recent orders grid just for the sales order grid. What should I change in my code ?

Thx

Answer 1

Not the best option, but it works (temporal coupling):

 private $grid;

 public function beforeBlockToHtml(Varien_Event_Observer $observer)
    {
        $this->grid = $observer->getBlock();
        /**
         * Mage_Adminhtml_Block_Sales_Order_Grid
         */
        if ($this->grid instanceof Mage_Adminhtml_Block_Sales_Order_Grid) {
            $this->grid ->addColumnAfter(
                'customer_increment_id',
                [
                    'header' => Mage::helper('ffm_codebin')->__('Customer Inc.'),
                    'index'  => 'customer_increment_id',
                    'filter_index' => 'c.increment_id'
                ],
                'entity_id'
            );
        }
    }
 public function beforeCollectionLoad(Varien_Event_Observer $observer)
    {
        $collection = $observer->getCollection();
        if(!isset($collection)){
            return;
        }

        if($collection instanceof Mage_Sales_Model_Resource_Order_Grid_Collection && $this->grid instanceof Mage_Adminhtml_Block_Sales_Order_Grid){
            $collection->getSelect()->join(['c' => $collection->getTable('customer/entity')]
                ,'main_table.customer_id = c.entity_id', ['customer_increment_id' => 'c.increment_id']
            );
        }
    }