Hi Cojocareanu Cosmin-Florentin
I guess you need a helper non-persistable entity with the search attribute let's say email in the page set the main object of the page this entity inside it put your data grid with a MF data source inside the data view in that case you a param of type Helper will be in the DS MF make a decision to see if the $helper/email is empty to retrieve all records of if it has any emails to retrieve the record that you are looking for.
I hope I simplified the scenario
Please recommend this as an accepted answer if it answers your question
Thanks