I am trying to add row to wpdatatable object just before it renders. Here is what I got:

add_filter('wpdatatables_filter_initial_table_construct', 'alter_msds_table', 10 , 1);
function alter_msds_table($table_data) {
    global $post, $product; $sku = $product->get_sku();    
    $rows[] = array(
        'COALESCE(changes.text, sds.text)' => $sku,
        'ftype' => '',
        'id' => '0',
        'name' => 'Catalog Number',
        'wdt_ID' => '150',
        );
    $rows[] = array(
        'COALESCE(changes.text, sds.text)' => $post->post_title,
        'ftype' => '',
        'id' => '0',
        'name' => 'Product Name',
        'wdt_ID' => '151',
    );
    $table_data->addRows( $rows );
    return $table_data;
}

And I get "Please provide a proper wpDataTables Row" from function addWDTRow. It checks for instanceof WDTRow, but I cannot find such class.

How do I add row?

Thanks

Generally it is so, but here I am using hook/s  that you provided, which should do the job. There is existing function in your class which I also can use (addRows). But the fact that it checks for instance of "WDTRow" (class I presume), which does not exist anywhere in the code, makes me think that this may be a bug. If this is a bug, I'll expect a fix, and if its not a bug and I am wrong, than your previous message is relevant.

Ok, only now I got around to deal with this. Editing the class was my last option as I wanted to avoid touching your code to be able to update the plugin later automatically. Anyway since there is no other option for this, I have altered 2 functions, and it works fine now. You might want to add those insted of existing ones in future updates.

public function addWDTRow( $row ) {
        if( count( $this->_wdtIndexedColumns ) == 0 ) {
            throw new WDTException('Please add columns to wpDataTable first.');
        }
        if( count($row) != $this->countColumns() ) {
            throw new WDTException( 'Count of the columns in table and in row is not equal. Row: '.count($row).', table: '.$this->countColumns() );
        }
        apply_filters( 'wdt_add_row', $row );
        $this->_dataRows[] = &$row;
    }
    public function addRows( &$rows ) {
        if( !is_array( $rows ) ) {
            throw new WDTException('Please provide an array of WDTRow objects.');
        }
        apply_filters( 'wdt_add_dataRows', $rows );
        foreach( $rows as &$row ) {
            $this->addWDTRow( $row );
        }
    }

You should however pay attention here:

 if( count($row) != $this->countColumns() ) {

This test might not be enough, since it does not test if array keys (column names) are right. If it was me, I'd do a function for addRows which only receives values and combines them with the right column names.

Anyway hope this will help you a bit.

Thanks