Returning a downloadable file using a stream in asp.net web forms - asp.net

Question

In asp.net MVC I can do something like the following which will open a stream:
Stream strm1 = GenerateReport(Id);
return File(strm1,
"application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
"Report_" + reportId.ToString() + ".xlsx");
Notice how I am passing strm1 which is a stream. I can then name it Report_+ ...xlsx like the example above shows.
Is there a similar way to do this with asp.net web forms using c#.

Answer 1

You can use TransmitFile or WriteFile if the file is in your website folder.
string fileName = string.Format("Report_{0}.xlsx", reportId);
Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
Response.AddHeader("Content-Disposition",
string.Format("attachment; filename={0}", fileName));
Response.TransmitFile(fileName);
Response.End();
Stream
If your data is already in Memory, you want this method which writes the response in chunks.
Stream stm1 = GenerateReport(Id);
Int16 bufferSize = 1024;
byte[] buffer = new byte[bufferSize + 1];
Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
Response.AddHeader("Content-Disposition",
string.Format("attachment; filename=\"Report_{0}.xlsx\";", reportId));
Response.BufferOutput = false;
int count = stm1.Read(buffer, 0, bufferSize);
while (count > 0)
{
Response.OutputStream.Write(buffer, 0, count);
count = stm1.Read(buffer, 0, bufferSize);
}

Answer 2

I use this extension to send a stream as a downloadable file:
public static class ToDownloadExtention
{
public static void ToDownload(this Stream stream, string fileName, HttpResponse response)
{
response.Clear();
response.ContentType = "application/octet-stream";
response.AddHeader("Content-Disposition", string.Format("attachment; filename={0}", fileName));
stream.CopyTo(response.OutputStream);
response.End();
}
}
And the usage is:
var stream = new MemoryStream();
stream.ToDownload("someFileName.ext",Response);

Answer 3

Or if you have a stream ready to be written, simply copy it to response stream:
Response.Clear();
Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
Response.AddHeader("Content-Disposition", "attachment; filename={your file name}");
Response.OutputStream.Write(stream, 0, stream.length);
Response.End();
Added same code just for visibility