get_filtered_n_rows

Get the total number of filtered rows in this if a filter has been applied.

As new rows (rows added to the proxy and not yet added to the proxied data model) and rows to remove (rows marked for removal but not yet removed from the proxied data model) are also filtered, the returned number also contains references to new rows and rows to be removed.

Parameters:

this	a DataProxy object

Returns:

the number of filtered rows in this, or -1 if no filter has been applied