Get current dashboard in getSearhObject

Currently I am hardcoding the dashboard name in the script "$srchObj1 = SearchClause::getSearchObject($table, "Dashboard"); " in the a chart's after table initialised event in order to set up the search object. Now, the same chart may appear in multiple dashboards, is there any variable similar to $table which stores the current dashbaord name? It seems $dashboard is not the answer. Thanks.

Best regards,
Jack Tong