Redirecting to MVC ActionResult from FileResult

问题

This might be a simple one but here goes:

I'm implementing an excel downloadable report in my MVC3 application. I've used this method in the past and it's worked perfectly, however in this case, there is a chance that sales data may not exist for the report. Here is my code:

I have a FileResult action within a Reports controller:

    [HttpPost]
    public FileResult ExcelReportDownload(ReportExcelDownloadRequest reportRequest)
    {
        ReportEngine re = new ReportEngine();

        Stream report = re.GetReport(reportRequest);

        return new FileStreamResult(report, "application/ms-excel")
        {
            FileDownloadName = "SalesReport.xls"
        };
    }

My issue is that sometimes the report stream may be null meaning that there's no sales info available, in which case I would rather redirect to a View that displays a message to say there is no sales information available, however I am not sure how to achieve this.

Is there a way to do this?

回答1:

Well, FileResult inherits from ActionResult :

If you result can be either a RedirectToRouteResult (inheriting from ActionResult) or a FileResult, then... your action must be of type ActionResult, which can manage both.

something like that :

    [HttpPost]
    public ActionResult ExcelReportDownload(ReportExcelDownloadRequest reportRequest)
    {
        ReportEngine re = new ReportEngine();

        Stream report = re.GetReport(reportRequest);
        if (report == null)
           return RedirectToAction(<action Name>);
        else
           return new FileStreamResult(report, "application/ms-excel")
           {
               FileDownloadName = "SalesReport.xls"
           };
    }

来源：https://stackoverflow.com/questions/11434345/redirecting-to-mvc-actionresult-from-fileresult