The Document object's print method has an overload which allows passing in true/false for "show print dialog" and "show progress dialog". From the documentation the signature is below:
public bool Print(
bool showPrintDialog,
bool showPrintProgressDialog,
bool usePrintingThread
)
You might call it on a report that as follows:
var myReport = new SalesActiveReport();
myReport.Run();
myReport.Document.Print(false, false, false);