我在这里找到了解决方案。
var actionPDF = new Rotativa.ActionAsPdf("YOUR_ACTION_Method", new { id = ID, lang = strLang } //some route values)
{
//FileName = "TestView.pdf",
PageSize = Size.A4,
PageOrientation = Rotativa.Options.Orientation.Landscape,
PageMargins = { Left = 1, Right = 1 }
};
byte[] applicationPDFData = actionPDF.BuildPdf(ControllerContext);