Hi, I need to check if subreport finished loading, how can do this and on what event?

I now have this code to pupulate my unbound textbox on current event:
Me.Text51 = ConvertDocumentsToEnglish([rpt_mysubreport].[Report].[my_subreport_control])

It works but I would like to make sure if it's loaded and particulary if control named "my_subreport_control" is loaded because that where I get my data from and it's last control on the subreport that calculates record count.