[c#] How to return PDF to browser in MVC?

I have this demo code for iTextSharp

    Document document = new Document();
    try
    {
        PdfWriter.GetInstance(document, new FileStream("Chap0101.pdf", FileMode.Create));

        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();

How do I get the controller to return the pdf document to the browser?

EDIT:

Running this code does open Acrobat but I get an error message "The file is damaged and could not be repaired"

  public FileStreamResult pdf()
    {
        MemoryStream m = new MemoryStream();
        Document document = new Document();
        PdfWriter.GetInstance(document, m);
        document.Open();
        document.Add(new Paragraph("Hello World"));
        document.Add(new Paragraph(DateTime.Now.ToString()));
        m.Position = 0;

        return File(m, "application/pdf");
    }

Any ideas why this does not work?

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");
}

You can create a custom class to modify the content type and add the file to the response.

http://haacked.com/archive/2008/05/10/writing-a-custom-file-download-action-result-for-asp.net-mvc.aspx

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");
}

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

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");
}

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

if the filename is generating dynamically then how to define filename here, it is generating through guid here.

if you return var-binary data from DB to display PDF on popup or browser means follow this code:-

View page:

@using (Html.BeginForm("DisplayPDF", "Scan", FormMethod.Post))
    {
        <a href="javascript:;" onclick="document.forms[0].submit();">View PDF</a>
    }

Scan controller:

public ActionResult DisplayPDF()
        {
            byte[] byteArray = GetPdfFromDB(4);
            MemoryStream pdfStream = new MemoryStream();
            pdfStream.Write(byteArray, 0, byteArray.Length);
            pdfStream.Position = 0;
            return new FileStreamResult(pdfStream, "application/pdf");
        }

        private byte[] GetPdfFromDB(int id)
        {
            #region
            byte[] bytes = { };
            string constr = System.Configuration.ConfigurationManager.ConnectionStrings["Connection"].ConnectionString;
            using (SqlConnection con = new SqlConnection(constr))
            {
                using (SqlCommand cmd = new SqlCommand())
                {
                    cmd.CommandText = "SELECT Scan_Pdf_File FROM PWF_InvoiceMain WHERE InvoiceID=@Id and Enabled = 1";
                    cmd.Parameters.AddWithValue("@Id", id);
                    cmd.Connection = con;
                    con.Open();
                    using (SqlDataReader sdr = cmd.ExecuteReader())
                    {
                        if (sdr.HasRows == true)
                        {
                            sdr.Read();
                            bytes = (byte[])sdr["Scan_Pdf_File"];
                        }
                    }
                    con.Close();
                }
            }

            return bytes;
            #endregion
        }

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 know this question is old but I thought I would share this as I could not find anything similar.

I wanted to create my views/models as normal using Razor and have them rendered as Pdfs.

This way I had control over the pdf presentation using standard html output rather than figuring out how to layout the document using iTextSharp.

The project and source code is available here with nuget installation instructions:

https://github.com/andyhutch77/MvcRazorToPdf

Install-Package MvcRazorToPdf

You would normally do a Response.Flush followed by a Response.Close, but for some reason the iTextSharp library doesn't seem to like this. The data doesn't make it through and Adobe thinks the PDF is corrupt. Leave out the Response.Close function and see if your results are better:

Response.Clear();
Response.ContentType = "application/pdf";
Response.AppendHeader("Content-disposition", "attachment; filename=file.pdf"); // open in a new window
Response.OutputStream.Write(outStream.GetBuffer(), 0, outStream.GetBuffer().Length);
Response.Flush();

// For some reason, if we close the Response stream, the PDF doesn't make it through
//Response.Close();