Parameters Prompt on Export

Question

I am using Crystal Reports 2008 to try to build an ASP.NET page that enables me to present reports we've written on the web, via Visual Studio 2008/IIS7/ASP.NET 3.5. The quick question is what event is fired when a user clicks on the export or print buttons in the CrystalReportViewer control?
The long question is that I am trying to build a custom interface for the report viewer, wherein that the user enters the parameters they need for the report in 'our' interface and then these values are added to the report using the ReportDocument.SetParameterValue method in the code-behind. However, the parameter values were lost when trying to do anything on the report. I have got search and page navigation working by using the much recommended technique of saving the report file into a Session variable, and rebinding the CrystalReportViewer to this session variable in the 'OnSearch' and 'OnNavigate' events. However, I can't work out how to do the same when trying to export or print the report.
I can't seem to find the answer elsewhere on the web - can anyone here help?
Many thanks.

Answer 1

Hello Adam. Thanks for your response.
I actually am resetting the report source in my Page_Load event as follows:
if (Session["report"] != null)
    crvReportViewer.ReportSource = Session["report"];
After the user has selected their parameters, they click a button which runs a function to create the ReportDocument, assign the parameters and add the ReportDocument to the session variable. That function is essentially as follows:
ReportDocument report = new ReportDocument();
string reportPath = strReportFilePath;
report.Load(reportPath);
String strReportDateFrom = txtReportDateFrom.Text;
String strReportDateTo = txtReportDateTo.Text;
report.SetParameterValue("ReportDateFrom", strReportDateFrom);
report.SetParameterValue("ReportDateTo", strReportDateTo);
Session.Add("report", report);
crvReportViewer.ReportSource = report;
Am I missing something here, as I can't get things like the Search to work unless I add the code at the top to the OnSearch event?
Many thanks.