Pdf file damaged on download in Chrome and Firefox - asp.net

Question

I am using iTextSharp for creating pdf reports (files) and storing those on the web server where my application resides. I am able to create the file, go into the storage folder and open the file without a problem. Notice: The user is not to get the file automatically
downloaded on creation.
I want to give the user the option to download "old" reports from the server with a button.
This is working fine in IE (10) but not in Chrome and Firefox. I always get the error message:
There was an error opening this document. The file is damaged and could not be repaired.
I have this image button and on click I send the user to a Generic Handler (since my page contains Update Panels) according to this post (only using it partially for now).
This is the code that actually downloads the file:
public void ProcessRequest(HttpContext context)
{
var _fileName = context.Request.QueryString["fileName"];
using (var _output = new MemoryStream())
{
//var _fileSeverPath = context.Server.MapPath(_fileName);
context.Response.Clear();
context.Response.ContentType = "application/pdf";// "application/pdf";
//context.Response.AppendHeader("Content-Length", _fileName.Length.ToString());
context.Response.AppendHeader("Content-Disposition", string.Format("attachment; filename=" + Path.GetFileName(_fileName)));
context.Response.WriteFile(_fileName);
context.Response.Flush();
context.Response.Close();
context.Response.End();
}
}
As I said, this works fine in IE but not in Chrome and Firefox.
When I open the file in Notepad it seams that I only get about 1/3 of the file when downloaded in Chrome and Firefox.
Any suggestions would be greatly appreciated. Been trying to resolve this for a few days now..

Answer 1

From HttpResponse.WriteFile Method (String)
When this method is used with large files, calling the method might
throw an exception. The size of the file that can be used with this
method depends on the hardware configuration of the Web server. For
more information, see article 812406, "PRB: Response.WriteFile Cannot
Download a Large File" on the Microsoft Knowledge Base Web site.
Try this instead:
public void ProcessRequest(HttpContext context)
{
var _fileName = context.Request.QueryString["fileName"];
context.Response.Clear();
context.Response.Buffer = true;
context.Response.ContentType = "application/pdf";
context.Response.AppendHeader(
"Content-Disposition",
string.Format("attachment; filename=" + Path.GetFileName(_fileName)));
using (var fs = new FileStream(_fileName, FileMode.Open, FileAccess.Read))
{
using (var sr = new StreamReader(fs, true))
{
int length = (int)fs.Length;
byte[] buffer;
using (BinaryReader br = new BinaryReader(fs, sr.CurrentEncoding))
{
buffer = br.ReadBytes(length);
context.Response.BinaryWrite(buffer);
}
}
}
context.Response.Flush();
context.Response.Close();
context.Response.End();
}

Answer 2

Ok, FINALLY.. I found the solution and it makes me feel like a fool at the same time..
Removed context.Response.Close(); ...then everything worked perfectly :)