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I'm trying to download PDF file using C# and asp.net

using the following code I'm trying to download pdf file from server path but after clicking on download button file not download but the code gets file name and file path.
I think I'm missing something in code so, please help me out
Thank you in advance..
code is :
protected void btn_Download_Template_Click(object sender, EventArgs e)
{
string mainPath = "";
string fileName = "Self_Declaration.pdf";
mainPath = Server.MapPath("~/Template/Self_Declaration.pdf");
FileInfo file = new FileInfo(mainPath);
if (file.Exists)
{
Response.Clear();
Response.ClearHeaders();
Response.ClearContent();
Response.AddHeader("content-disposition", "attachment; filename= ~/Template/Self_Declaration.pdf");
Response.AddHeader("Content-Type", "application/pdf");
Response.ContentType = "application/pdf";
Response.WriteFile(file.FullName);
Response.End();
}
else
{
Response.Write("This file does not exist.");
}
}```

Well I don't have enough reputation points to put this in the comment section, but I think your question has already been answered here

Cannot download files/images from uploads folder in asp.net

i need to download images that i stored in folder in asp.net web application name as uploads
i got a function that should download this as
private void downloadAnImage(string strImage)
{
Response.ContentType = "image/jpg";
Response.AppendHeader("Content-Disposition", "attachment; filename=" + strImage);
Response.TransmitFile(strImage);
Response.End();
}
and i call this function from link button as
protected void lnkDwnSlc_Click(object sender, EventArgs e)
{
if (Session["slc_filepath"] != null)
{
string path = Server.MapPath(Session["slc_filepath"].ToString());
downloadAnImage(path);
}
}
where Session["slc_filepath"] is path stored in session
but after running this code file/image is not downloading and I got no error about why file is not downloading. And I checked file path by using breakpoint , it is correct,
I search a lot form google but i can't understand where I missed something.
EDIT:
on page load event i pull records from table there i saved path of file and in session i store it like
Session["slc_filepath"] = dt.Rows[0]["UploadSLC"].ToString();
where UploadSLC is column name of table where i store path of image
and in database string is looking as
~\uploads\ab071770-473a-4e1a-8cfc-addeccf565d5.jpg

I found answer after a long searching but a hint i got is from my junior in my team i really appreciate it, i just added
ScriptManager scriptManager = ScriptManager.GetCurrent(this.Page);
scriptManager.RegisterPostBackControl(this.lnkDwnSlc);
in pageLoad event because i am using update panel and script manager in my aspx page and bootstrap for design so it stopped functionality
after doing so it works like a charm,
thanks all of your efforts and support,

Try this:
private void downloadAnImage(string strImage)
{
Response.Clear();
Response.ContentType = "image/jpg";
Response.AppendHeader("Content-Disposition", "attachment; filename=" + strImage);
Response.TransmitFile(strImage);
Response.Flush();
Response.End();
}
Happy to help you!

I suggest to troubleshoot the issue where it came from.
Try a hardcoded path (to make sure, you are passing the correct path)
//try forward or back slash, make sure the file exists
string path = Server.MapPath("~/uploads/ab071770-473a-4e1a-8cfc-addeccf565d5.jpg");
Try this:
private void downloadAnImage(string strImage)
{
Response.ContentType = "image/jpg";
Response.AppendHeader("Content-Disposition", "attachment; filename=" + strImage);
Response.TransmitFile(strImage);
Response.Flush();
Response.End();
}
Make sure there's no javascript error that is being thrown on the client side.

Please correct your path of image while binding from database
like "~/Image/images.png ".
PFB of my snippet code you may supposed to get solution.
protected void Page_Load(object sender, EventArgs e)
{
Session["slc_filepath"] = "~/Image/images.png";
}
protected void LinkButton1_Click(object sender, EventArgs e)
{
string path = Server.MapPath(Session["slc_filepath"].ToString());
downloadAnImage(path);
}
private void downloadAnImage(string strImage)
{
Response.ContentType = "image/jpg";
Response.AppendHeader("Content-Disposition", "attachment; filename=" + strImage);
Response.TransmitFile(strImage);
Response.End();
}

Use an ashx Handler like this http://www.intstrings.com/ramivemula/asp-net/how-to-download-files-from-server-to-client-using-a-generic-handler/
Then send by ajax a window.Open to the new ashx.

mp3 files not getting downloaded?

I have written the below lines of code in c#
private void DownloadFile(byte[] myData, string Name)
{
Response.Expires = 0;
Response.Clear();
string ext= System.IO.Path.GetExtension(Name);
switch(ext)
{
case ".mp3":
Response.ContentType = "audio/mpeg";
break;
default:
Response.ContentType = "Application/octet-stream";
break;
}
Response.AddHeader("content-length", myData.Length.ToString());
Response.AddHeader("Content-Disposition", "attachment; filename=" + Name);
try
{
Response.BinaryWrite(myData);
}
catch { }
Response.Flush();
Response.End();
}
Now the issue is that whenever we click mp3 file to download, it's directly played. I want that it should download it. Also I want that all types of files should be downloaded.

I struggled with this for the longest time, but finally solved the puzzle. Use Response.WriteFile. You could follow it with Response.Flush but I found that to be unnecessary. Extra headers were not necessary with .mp3 files. In my case, the .mp3 files were in a folder directly under the root. And here's a bonus: The key ingredients for making the .mp3 download work with smartphones (which was my dilemma) were using Response.End, and telling the mobile device that the download was done by sending back the Response.StatusCode = 200.
string FilenameMP3 = "~/someFolder/xyz.mp3";
string headerFilename = Filename.Substring(Filename.IndexOf("/") + 1);
Response.AppendHeader("Content-Disposition", String.Concat("attachment;filename=\"", headerFilename, "\""));
Response.ContentType = "audio/mpeg";
try
{
Response.WriteFile(Filename, true);
Response.End();
}
finally
{
Response.StatusCode = 200;
Response.Close();
}

What you have should be sufficient, assuming that the headers you added aren't being stripped / corrupted in transit (simple to check via Fiddler or similar).
Since you don't want the browser to interpret this data, a pragmatic option might be to simply send all data as "application/octet-stream", regardless of the content. While the "attachment" disposition should be sufficient for this, this approach is explicitly called out in RFC 2616, 19.5.1 ("Content-Disposition"):
If this header is used in a response with the application/octet- stream content-type, the implied suggestion is that the user agent should not display the response, but directly enter a `save response as...' dialog.

Create text file and download

I'm trying to write to a text file in memory and then download that file without saving the file to the hard disk. I'm using the StringWriter to write the contents:
StringWriter oStringWriter = new StringWriter();
oStringWriter.Write("This is the content");
How do I then download this file?
EDIT:
It was combination of answers which gave me my solution. Here it is:
StringWriter oStringWriter = new StringWriter();
oStringWriter.WriteLine("Line 1");
Response.ContentType = "text/plain";
Response.AddHeader("content-disposition", "attachment;filename=" + string.Format("members-{0}.csv",string.Format("{0:ddMMyyyy}",DateTime.Today)));
Response.Clear();
using (StreamWriter writer = new StreamWriter(Response.OutputStream, Encoding.UTF8))
{
writer.Write(oStringWriter.ToString());
}
Response.End();

This solved for me:
MemoryStream ms = new MemoryStream();
TextWriter tw = new StreamWriter(ms);
tw.WriteLine("Line 1");
tw.WriteLine("Line 2");
tw.WriteLine("Line 3");
tw.Flush();
byte[] bytes = ms.ToArray();
ms.Close();
Response.Clear();
Response.ContentType = "application/force-download";
Response.AddHeader("content-disposition", "attachment; filename=file.txt");
Response.BinaryWrite(bytes);
Response.End();

Instead of storing the data in memory and then sending it to the response stream, you can write it directly to the response stream:
using (StreamWriter writer = new StreamWriter(Response.OutputStream, Encoding.UTF8)) {
writer.Write("This is the content");
}
The example uses the UTF-8 encoding, you should change that if you are using some other encoding.

Basically you create an HttpHandler by implementing the IHttpHandler interface. In the ProcessRequest method you basically just write your text to context.Response. You also need to add a Content-Disposition http header:
context.Response.AddHeader("Content-Disposition", "attachment; filename=YourFileName.txt");
Also remember to set the ContentType:
context.Response.ContentType = "text/plain";

Just a small addition to the other answers. At the very end of a download I execute:
context.Response.Flush();
context.ApplicationInstance.CompleteRequest();
I learned that otherwise, the download sometimes does not complete successfully.
This Google Groups posting also notes that Response.End throws a ThreadAbortException which you could avoid by using the CompleteRequest method.

I had many issues with this. Finnaly found a solution that seems to work everytime.
In most cases the user is going to click a button for the download. At this point it is best to redirect the page back to the same spot. add a parameter in the url that you can grab and read.
example( www.somewhere.com/mypage.aspx?print=stuff)
<asp:Button ID="btn" runat="server" Text="print something" OnClick="btn_Click" />
protected void Page_Load(object sender, EventArgs e) {
if (Request["print"] == "stuff") { Print("my test content"); }
}
/* or pass byte[] content*/
private void Print(string content ){
Response.ContentType = "text/plain";
Response.AddHeader("content-disposition", "attachment;filename=myFile.txt");
// Response.BinaryWrite(content);
Response.Write(content);
Response.Flush();
Response.End();
}
protected void btn_Click(object sender, EventArgs e) {
// postbacks give you troubles if using async.
// Will give an error when Response.End() is called.
Response.Redirect(Request.Url + "?print=queue");
}

Extension of #Vinicious answer.
I had data that could contain commas. The common solution is to escape that piece of data by enclosing it in quotes, while making sure to also escape quotes that could also be a part of the data.
One rub I came against and a warning when writing CSV, excel will not like you if you put spaces trailing your commas. discovered solution to my problem from superuser answer
protected void btnDownload_Click(object sender, EventArgs e)
{
MemoryStream ms = new MemoryStream();
TextWriter tw = new StreamWriter(ms, System.Text.Encoding.UTF8);
var structures = KAWSLib.BusinessLayer.Structure.GetStructuresInService();
// *** comma delimited
tw.Write("Latitude, Longitude, CountySerial, StructureType, Orientation, District, RoutePre, RouteNo, LocationDesc");
foreach (var s in structures)
{
tw.Write(Environment.NewLine + string.Format("{0:#.000000},{1:#.000000},{2},{3},{4},{5},{6},{7},{8}", s.LATITUDE, s.LONGITUDE, s.CO_SER, EscapeIfNeeded(s.SuperTypeLookup.SHORTDESC), EscapeIfNeeded(s.OrientationLookup.SHORTDESC), s.DISTRICT, s.ROUTE_PREFIX, s.RouteValue, EscapeIfNeeded(s.LOC_DESC)));
}
tw.Flush();
byte[] bytes = ms.ToArray();
ms.Close();
Response.Clear();
Response.ContentType = "application/force-download";
Response.AddHeader("content-disposition", "attachment; filename=" + string.Format("kaws-structures-{0:yyyy.MM.dd}.csv", DateTime.Today));
Response.BinaryWrite(bytes);
Response.End();
}
string EscapeIfNeeded(string s)
{
if (s.Contains(","))
{
return "\"" + s.Replace("\"", "\"\"") + "\"";
}
else
{
return s;
}
}
Below will cause a problem for excel. In excel the first quote will become part of the data and consequently than separate at the embedded comma. Spaces bad.
tw.Write(Environment.NewLine + string.Format("{0:#.000000}, {1:#.000000}, {2}, {3}, {4}, {5}, {6}, {7}, {8}", s.LATITUDE, s.LONGITUDE, s.CO_SER, EscapeIfNeeded(s.SuperTypeLookup.SHORTDESC), EscapeIfNeeded(s.OrientationLookup.SHORTDESC), s.DISTRICT, s.ROUTE_PREFIX, s.RouteValue, EscapeIfNeeded(s.LOC_DESC)));

This is very simple, and the answer can be seen in this Microsoft KB Article: How to write binary files to the browser using ASP.NET and C#

Correct usage of Response.Write() in ASP.NET

I am trying to force a download of an XML file when the user visits a page.
This is the code I am using
public partial class GenerateTemplate : LayoutsPageBase
{
protected void Page_Load(object sender, EventArgs e)
{
//.............
//Going about generating my XML
//.............
Response.ClearContent();
Response.AddHeader("content-disposition", "attachment; filename=template.xml");
Response.Write(xmlDoc.InnerXml);
Response.Flush();
Response.Close();
}
}
I am facing a problem that my download window hangs indefinitely, without ever completing the download/Open of the file.
What am I doing wrong? Am I not disposing any objects or closing any connections here?

I've posted a reply to a similar question. To quote myself:
Just a small addition to the other answers. At the very end of a download I execute:
context.Response.Flush();
context.ApplicationInstance.CompleteRequest();
I learned that otherwise, the download sometimes does not complete successfully.
This Google Groups posting also notes that Response.End throws a ThreadAbortException which you could avoid by using the CompleteRequest method.

Try using Response.End() instead of Flush and Close
That's what I have been using in the past.

Have you tried setting the content type and calling Response.End():
protected void Page_Load(object sender, EventArgs e)
{
//.............
//Going about generating my XML
//.............
Response.Clear();
Response.ContentType = "text/xml";
Response.AddHeader("Content-Disposition", "attachment; filename=template.xml");
Response.Write(xmlDoc.InnerXml);
Response.End();
}

You say you want to have a file download With asp.net web forms you would do this:
context.Response.ContentType = //MIME type
// Set the filename
context.Response.AddHeader("content-disposition", "attachment;filename=" + queryFile);
// Stream the file to the client
context.Response.WriteFile(file);