Copy    protected function _prepareColumns()
    {
        $this->addColumn('apply_to_product', [
            'header_css_class' => 'a-center',
            'type'      => 'checkbox',
            'name'      => 'apply_to_product',
            'field_name' => 'selected_products[]',
            'values'    => $this->_getSelectedProducts(),
            'align'     => 'center',
            'index'     => 'product_id'
        ]);
    }

    protected function _getSelectedProducts()
    {
        return $this->getRequest()->getPost('selected_products', []);
    }

    /**
     * Retrieve AJAX URL for grid when filtering or resetting 
     *
     * @return string
     */
    public function getGridUrl()
    {
        return $this->getUrl('*/*/product', ['_current'=>true]);
    }

Copy        // Specify the currency code.
        $this->addColumn('unit_price', [
            'header'    => $helper->__('Unit Price'),
            'index'     => 'unit_price',
            'width'     => '80px',
            'sortable'  => false,
            'filter'    => false,
            'type'  => 'currency',
            'currency_code' => 'MYR',
        ]);
        
        // Currency code is specified in another column.
        $this->addColumn('billing_amount', [
            'header' => $helper->__('Billing Amount'),
            'index' => 'billing_amount',
            'type'  => 'currency',
            'currency' => 'billing_currency_code',
        ]);

Copy        $this->addColumn('created_at', [
            'header'    => $helper->__('Requested At'),
            'index'     => 'created_at',
            'type'      => 'datetime',
            'width'     => '100px',
            'align'     => 'center',
            'filter_index' => 'main_table.created_at',
            'gmtoffset' => true
        ]);
        
       $this->addColumn('pickup_at', [
            'header'    => $helper)->__('Pickup At'),
            'width'     => '80px',            
            'index'     => 'pickup_at',
            'start_time'=> 'o_created_at', //order creaton time
            'cond'      => 'order_lot_id', //condition: if !order_lot_id then return ''
            'format'    => 'h:m:s a',
            'renderer'  => 'patron/adminhtml_order_grid_renderer_duration',
            'filter'    => false,
            'sort'      => false
        ]);
        
        $this->addColumn('to_deliver_at', [
            'header'    => $helper->__('To Deliver At'),
            'width'     => '80px',            
            'index'     => 'to_deliver_at',
            'start_time'=> 'o_created_at', //order creaton time
            'cond'      => 'order_id', //condition: if !order_id then return ''
            'format'    => 'h:m:s a',
            'renderer'  => 'patron/adminhtml_order_grid_renderer_duration',
            'filter'    => false,
            'sort'      => false
        ]);

Copy        $this->addColumn('action', [
            'header'    =>  $helper->__('Action'),
            'width'     => '50px',
            'type'      => 'action',
            'getter'    => 'getCompanyId', // Only one possible getter for row.
            'actions'   => [ // Can fit multiple actions.
                [
                    'caption' => $helper->__('Utilization'),
                    'popup' => true, // Popup new browser window.
                    'url' => [
                        'base' => '*/*/utilization',
                        'params' => [
                            'member_id' => $this->getMemberId(),
                            //'plan_id => $row->getPlanId(), // No can do!
                        ]
                    ],
                    'field'   => 'company_id' // Merge to params: 'company_id' => $row->getCompanyId()                ]
            ],
            'filter'    => false,
            'sortable'  => false,
        ]);

Copy        $this->addColumn('action', [
            'header'    =>  $helper->__('Action'),
            'width'     => '50px',
            'type'      => 'action',
            'getter'    => [$this, 'getFilterParams'],
            'actions'   => [
                [
                    'caption' => $helper->__('Utilization'),
                    'popup' => true,
                    'url' => ['base' => '*/utilization'],
                    'field'   => 'filter'
                ]
            ],
            'filter'    => false,
            'sortable'  => false,
        ]);

        return parent::_prepareColumns();
    }

    /**
     *
     * @param Varien_Object $row
     * @return string
     */
    public function getFilterParams(Varien_Object $row)
    {
        $params = "company={$row->getCompanyId()}&member_id={$this->getMemberId()}&plan={$row->getPlanId()}";
        return Mage::helper('core/string')->urlEncode($params);
    }

Copy        $this->addColumn('entity_id', array(
            'header'    => Mage::helper('moe')->__('Med#'),
            'width'     => '30px',
            'index'     => 'entity_id',
            'filter_index'=>'main_table.entity_id'
        ));
        $this->addColumn('amount', [
            'header'=> $helper->__('Amount'),
            'width' => '80px',
            'index' => 'amount',
            'type'  => 'number'
        ]);
        $this->addColumn('response_body', array(
            'header'    => Mage::helper('moe')->__('Response Body'),
            'index'     => 'response_body',
            'sortable'  => false,
            'filter'    => false,
            'type'      => 'text', // uses 'adminhtml/widget_grid_column_renderer_longtext'
            'truncate'  => 420,
            'frame_callback' => array($this, 'extractData'),
            'noescape'  => false
        ));

        $this->addColumn('enabled', array(
            'header'    => Mage::helper('moe')->__('Enabled'),
            'align'     => 'left',
            'width'     => '60px',
            'index'     => 'enabled',
            'type'      => 'options',
            'options'   => array(
                1 => Mage::helper('moe')->__('Yes'),
                0 => Mage::helper('moe')->__('No')
            ),
        $this->addColumn('amount', array(
            'header'    => Mage::helper('accountpayment')->__('Amount'),
            'type'      => 'currency',
            'currency'  => 'currency_code',
            'width'     => 80,
            'index'     => 'amount'
        ));
        $options = Mage::getSingleton('sales/order_config')->getStatuses();
        $options['require_correction_follow_up'] = $this->__('Follow up for required correction');
        $this->addColumn('status', array(
            'header' => Mage::helper('sales')->__('Status'),
            'index' => 'status',
            'type'  => 'options',
            'width' => '200px',
            'filter'=> 'adminhtml/widget_grid_column_filter_text',
            'options' => $options,
            'filter_condition_callback' => array($this, '_statusFilter')
        )); 
        
        // ref: Mage_Adminhtml_Block_Catalog_Category_Tab_Product
        $this->addColumn('crosslink', array(
            'header_css_class' => 'a-center',
            'type'      => 'checkbox',
            'name'      => 'crosslink',
            'values'    => $this->_crosslinkStundetIds,
            'align'     => 'center',
            'index'     => 'entity_id'
        ));
        $this->addColumn('country_id', array(
            'header'    => Mage::helper('swms')->__('Country'),
            'index'     => 'country_id',
            'width'     => '100',
            'type'      => 'country',
        ));
        

Copy// Define param 'renderer' => 'patron/adminhtml_order_grid_renderer_duration in addColumn()
class Sxxxxx_Patron_Block_Adminhtml_Order_Grid_Renderer_Duration extends Mage_Adminhtml_Block_Widget_Grid_Column_Renderer_Datetime
{
    public function render(Varien_Object $row)
    {
        $col = $this->getColumn();
        //if no order lot, can't pickup
        if (!$row->getData($col->getCond())) {
            return '';
        }
        $time2 = $row->getData($col->getIndex()); //UTC
        $time1 = strtotime($row->getData($col->getStartTime()));        
        if ($time2) {
            $strRender = parent::render($row);
            $minutes = round((strtotime($time2) - $time1)/60, 0);
            $strRender .= " <$minutes>";
        } else {
            $minutes = round((time() - $time1)/60, 0);
            $strRender = "<$minutes>";
        }        
        return $strRender;
    }
}

Copy        // ...
        $this->addColumn('admin_updated_at', array(
            'header'    => Mage::helper('module')->__('Updated At'),
            'index'     => 'admin_created_at',
            'type'      => 'datetime',
            'frame_callback' => [$this, 'decorateUserUpdatedAt'],
        ));
        //...
        
    /**
     * @param string $value
     * @param Varien_Object $row
     * @param Mage_Adminhtml_Block_Widget_Grid_Column $column
     * @param bool $isExport
     * @return string
     */
    public function decorateUserUpdatedAt($value, $row, $column, $isExport)
    {
        if (!$isExport && $value > $row->getAdminUpdatedAt()) {
            $cell = '<strong><span class="not-available">' . $value . '</span></strong>';
        } else {
            $cell = $value;
        }
        return $cell;
    }

Copyclass Mage_Adminhtml_Block_Widget_Grid_Column_Renderer_Longtext
    extends Mage_Adminhtml_Block_Widget_Grid_Column_Renderer_Abstract
{
    /**
     * Render contents as a long text
     *
     * Text will be truncated as specified in string_limit, truncate or 250 by default
     * Also it can be html-escaped and nl2br()
     *
     * @param Varien_Object $row
     * @return string
     */
    public function render(Varien_Object $row)
    {
        $truncateLength = 250;
        // stringLength() is for legacy purposes
        if ($this->getColumn()->getStringLimit()) {
            $truncateLength = $this->getColumn()->getStringLimit();
        }
        if ($this->getColumn()->getTruncate()) {
            $truncateLength = $this->getColumn()->getTruncate();
        }
        $text = Mage::helper('core/string')->truncate(parent::_getValue($row), $truncateLength);
        if ($this->getColumn()->getEscape() !== FALSE) {
            $text = $this->escapeHtml($text);
        }
        if ($this->getColumn()->getNl2br()) {
            $text = nl2br($text);
        }
        return $text;
    }
}

Copy    /**
     * Convert the status dropdown for filtering to autocompleter   
     */         
    public function getAdditionalJavaScript()
    {      
        return $this->getLayout()
            ->createBlock('****/adminhtml_widget_grid_column_filter_autocompleter')
            ->setColumn($this->getColumn('status'))
            ->toHtml();
    }

Copy        $this->addColumn('apply_to', array(
            'header'    => Mage::helper('benefit')->__('Apply To'),
            'align'     => 'left',
            'index'     => 'apply_to',
            'renderer'  => 'benefit/adminhtml_attribute_grid_renderer_applyTo',
            'type'      => 'options',
            'options'   => Mage::helper('benefit')->getCustomerGroupOptionHash(),
            'filter_condition_callback' => [$this, '_findInSet'],
        ));
        
        return $this;
    }
    
    protected function _findInSet($collection, $column)
    {
        if ($value = $column->getFilter()->getValue()) {
            $collection->addFieldToFilter('apply_to', ['finset' => $value]);
        }
    }
    
    /**
     * Allow wildcard % in column search
     *
     * @param Mage_Core_Model_Resource_Db_Collection_Abstract $collection
     * @param Mage_Adminhtml_Block_Widget_Grid_Column $column
     */
    protected function _allowWildcardInFilter($collection, $column)
    {
        if ($value = $column->getFilter()->getValue()) {
            if ($field = $column->getFilterIndex() ?: $column->getIndex()) {
                /** @var Mage_Core_Model_Resource_Helper_Mysql4 $helper */
                $helper = Mage::getResourceHelper('core');
                $likeExpression = $helper->addLikeEscape($value, [
                    'position' => 'any',
                    'allow_string_mask' => true
                ]);
                $collection->addFieldToFilter($field, ['like' => $likeExpression]);
            }
        }
    }