合并PDF并返回FileContentResult

Question

我有一个ActionResult可以正常返回PDF。

public ActionResult TrainingHours(int id)
    {
        EmployeeModel model = new EmployeeModel(id);
        if (!model.CheckEmployeeAccess())
            throw new HttpException(403, "Access Denied");

        byte[] report = model.GetTrainingHoursReport(id);
        return File(report, Constants.PdfMimeType, model.EmployeeHoursReportFileName);
    }

byte []是从LocalReport的Render（＆＃34; PDF＆＃34;，DeviceInfoString）方法返回的，并且在下载时看起来很完美。

客户希望能够点击链接并为一组人运行相同的报告，并合并为一个pdf以供下载。

  public ActionResult MassTrainingHours(int[] employeeIds)
    {
        if (employeeIds == null)
            return new EmptyResult();

        List<byte[]> reportsList = new List<byte[]>();
        foreach (int employeeId in employeeIds)
        {
            EmployeeModel model = new EmployeeModel(employeeId);
            reportsList.Add(model.GetTrainingHoursReport(employeeId));
        }
        Post.Domain.Services.PdfMerger merger = new Post.Domain.Services.PdfMerger();
        byte[] report = merger.MergeFiles(reportsList);

        return File(report, Constants.PdfMimeType, "TrainingHours.pdf");

这是我的班级，使用iTextSharp合并pdf。

public class PdfMerger
{
    public byte[] MergeFiles(List<byte[]> inputFiles)
    {
        MemoryStream outputMS = new MemoryStream();
        Document document = new Document();
        PdfCopy writer = new PdfCopy(document, outputMS);
        writer.CloseStream = false;

        PdfImportedPage page = null;

        document.Open();

        foreach (byte[] fileData in inputFiles)
        {
            PdfReader reader = new PdfReader(fileData);
            int n = reader.NumberOfPages;

            for (int i = 1; i <= n; i++)
            {
                page = writer.GetImportedPage(reader, i);
                writer.AddPage(page);
            }

            PRAcroForm form = reader.AcroForm;
            if (form != null)
                writer.CopyAcroForm(reader);
        }

        document.Close();

        return outputMS.ToArray();
    }
}

这一切似乎都运行没有错误，但我从ActionResult中得到的绝对没有。

如果我在winforms应用程序上使用略微修改为FileStream的MergeFiles方法，则该过程可以顺利运行，并且我得到了我正在寻找的输出文件。