MVC json vs. ActionLink - asp.net-mvc

Question

new to programming. I am trying to print a PDF from MVC, it works well if I use Action Link, here is my code:
<%= Html.ActionLink("Print","GeneratePdf","Home", new { fc="Test" },null) %>
public ActionResult GeneratePdf(string fc)
{
Document document = new Document();
MemoryStream workStream = new MemoryStream();
PdfWriter.GetInstance(document, workStream);
document.Open();
document.Add(new iTextSharp.text.Paragraph("\n\n"));
// need to add the user name
iTextSharp.text.Paragraph p = new iTextSharp.text.Paragraph("Name: " + fc);
p.Alignment = 1;
document.Add(p);
document.Close();
byte[] byteInfo = workStream.ToArray();
SendPdfToBrowser(byteInfo);
return null;
}
public void SendPdfToBrowser(byte[] buf)
{
string filename = "Certificate.pdf";
// Prepare the headers.
Response.ClearContent();
Response.ClearHeaders();
Response.ContentType = "application/pdf";
Response.AddHeader("Content-Disposition", "attachment; filename=" + filename);
// Write the PDF data.
Response.BinaryWrite(buf);
// Flush the buffer to the browser.
Response.End();
Response.Flush();
Response.Clear();
}
I need to use Json, here is the code:
function PrintChart(fc) {
var fc = "Test";
var url = '<%= Url.Content("~/Home/GeneratePdf") %>';
$.post(url, { fc: fc },
function (content) {
if (content != null) { 5 }
}, "json");
<input type="button" onclick="PrintChart();" value="Print" />
I don't get any errors but it does not generate the PDF file. Thanks in advance.

Answer 1

You cannot use Ajax to download file. The jQuery $.post() will expect the response from the server is text.
To download file in a Ajax way, a general approach is to use a hidden iframe and set the src of the iframe to the URL of the file
<iframe id="hiddenFrame" src="" style="display:none; visibility:hidden;"></iframe>
In PrintChart() create URL including data as query-string and set the src of the iframe:
function PrintChart(fc) {
var fc = "Test";
var url = '<%= Url.Content("~/Home/GeneratePdf") %>';
url += "?fc="+fc;
$('#hiddenFrame').attr('src', url);
}