How to return PDF to browser in MVC?

Question

Return a FileContentResult. The last line in your controller action would be something like:

return File("Chap0101.pdf", "application/pdf");

If you are generating this PDF dynamically, it may be better to use a MemoryStream, and create the document in memory instead of saving to file. The code would be something like:

Document document = new Document();

MemoryStream stream = new MemoryStream();

try
{
    PdfWriter pdfWriter = PdfWriter.GetInstance(document, stream);
    pdfWriter.CloseStream = false;

    document.Open();
    document.Add(new Paragraph("Hello World"));
}
catch (DocumentException de)
{
    Console.Error.WriteLine(de.Message);
}
catch (IOException ioe)
{
    Console.Error.WriteLine(ioe.Message);
}

document.Close();

stream.Flush(); //Always catches me out
stream.Position = 0; //Not sure if this is required

return File(stream, "application/pdf", "DownloadName.pdf");

I got it working with this code.

using iTextSharp.text;
using iTextSharp.text.pdf;

public FileStreamResult pdf()
{
    MemoryStream workStream = new MemoryStream();
    Document document = new Document();
    PdfWriter.GetInstance(document, workStream).CloseStream = false;

    document.Open();
    document.Add(new Paragraph("Hello World"));
    document.Add(new Paragraph(DateTime.Now.ToString()));
    document.Close();

    byte[] byteInfo = workStream.ToArray();
    workStream.Write(byteInfo, 0, byteInfo.Length);
    workStream.Position = 0;

    return new FileStreamResult(workStream, "application/pdf");    
}

You must specify :

Response.AppendHeader("content-disposition", "inline; filename=file.pdf");
return new FileStreamResult(stream, "application/pdf")

For the file to be opened directly in the browser instead of being downloaded

If you return a FileResult from your action method, and use the File() extension method on the controller, doing what you want is pretty easy. There are overrides on the File() method that will take the binary contents of the file, the path to the file, or a Stream.

public FileResult DownloadFile()
{
    return File("path\\to\\pdf.pdf", "application/pdf");
}

I've run into similar problems and I've stumbled accross a solution. I used two posts, one from stack that shows the method to return for download and another one that shows a working solution for ItextSharp and MVC.

public FileStreamResult About()
{
    // Set up the document and the MS to write it to and create the PDF writer instance
    MemoryStream ms = new MemoryStream();
    Document document = new Document(PageSize.A4.Rotate());
    PdfWriter writer = PdfWriter.GetInstance(document, ms);

    // Open the PDF document
    document.Open();

    // Set up fonts used in the document
    Font font_heading_1 = FontFactory.GetFont(FontFactory.TIMES_ROMAN, 19, Font.BOLD);
    Font font_body = FontFactory.GetFont(FontFactory.TIMES_ROMAN, 9);

    // Create the heading paragraph with the headig font
    Paragraph paragraph;
    paragraph = new Paragraph("Hello world!", font_heading_1);

    // Add a horizontal line below the headig text and add it to the paragraph
    iTextSharp.text.pdf.draw.VerticalPositionMark seperator = new iTextSharp.text.pdf.draw.LineSeparator();
    seperator.Offset = -6f;
    paragraph.Add(seperator);

    // Add paragraph to document
    document.Add(paragraph);

    // Close the PDF document
    document.Close();

    // Hat tip to David for his code on stackoverflow for this bit
    // https://stackoverflow.com/questions/779430/asp-net-mvc-how-to-get-view-to-generate-pdf
    byte[] file = ms.ToArray();
    MemoryStream output = new MemoryStream();
    output.Write(file, 0, file.Length);
    output.Position = 0;

    HttpContext.Response.AddHeader("content-disposition","attachment; filename=form.pdf");


    // Return the output stream
    return File(output, "application/pdf"); //new FileStreamResult(output, "application/pdf");
}

FileStreamResult certainly works. But if you look at the Microsoft Docs, it inherits from ActionResult -> FileResult, which has another derived class FileContentResult. It "sends the contents of a binary file to the response". So if you already have the byte[], you should just use FileContentResult instead.

public ActionResult DisplayPDF()
{
    byte[] byteArray = GetPdfFromWhatever();

    return new FileContentResult(byteArray, "application/pdf");
}