SubReport in ReportViewer (VS2010)

Question

I have a problem when try to add a SubReport to a report. I'm using Visual Studio 2010. I've two report and two DataSet, one of every report. I've created master-report (report1 with DataSet) and i've added a subreport (report2 with DataSet1).

I've created this event in Form_Load:

this.reportViewer1.LocalReport.SubreportProcessing += new SubreportProcessingEventHandler(MySubreportProcessingEventHandler);

and this function:

void MySubreportProcessingEventHandler(object sender,SubreportProcessingEventArgs e) { e.DataSources.Add(new ReportDataSource("parameter1", "parameter2")); }

but i don't know what i've to write in parameter1 and parameter2.

my DataSet are:

DataSet with table A DataSet1 with table B

Someone can help me?