How to enable prompt for parameters before printing?

I am migrating an application from VB6 with Crystal Reports 11 to VB.NET with Crystal Reports for Visual Studio 2010. I have a report which contains Parameter Fields. When the report is viewed the viewer (I think) prompts for parameter values, but there is a problem with printing (.PrintToPrinter).

In VB6 .OpenReport shows the parameter prompt, but .Load used in VB.NET doesn't display anything and there is and error when printing (Missing Parameter Values).

Is there a way to force parameter prompt?

In VB6 I have (only key commands are included):

Set CrApp = New CRAXDRT.ApplicationSet rsData = ReportDataSet CrReport = CrApp.OpenReport(ReportFile) 'This command displays a parameter promptCrReport.database.SetDataSource ReportDataCrReport.PrintOut False, 1 

In VB.NET I have:

Dim CrReport As New CrystalDecisions.CrystalReports.Engine.ReportDocumentCrReport.Load(TemplateFilename)CrReport.SetDataSource(mResults) CrReport.PrintToPrinter(1, False, 0, 0)