SubreportprocessingEvent not firing

Can someone help with this, I have been doing my research , and alot of people having alot of problems, its hard to trace this.
I have subreports in the main report. Its not even executing the subreport, everytime i hit the toggle button, it saids data not retrieve, its never getting into the
LocalReport_SubreportProcessing function
protected void LocalReport_SubreportProcessing(object sender, Microsoft.Reporting.WinForms.SubreportProcessingEventArgs e)
{
e.DataSources.Add(new ReportDataSource("Datatable",this.BindingSource));

reportViewer.LocalReport.ReportEmbeddedResource = "Example.rdlc";
this.rDataSource.Value = this.Generic_DatatableBindingSource;
this.titleParameter = new ReportParameter("BookTitle", this.BookTitle);
this.reportViewer.LocalReport.SetParameters(new ReportParameter[] { titleParameter });
this.reportViewer.LocalReport.DataSources.Add(rDataSource);
this.reportViewer.LocalReport.Refresh();
this.reportViewer.RefreshReport();
}