Download txt file with ASP.NET Web Forms including HTML of the page in the file

Question

I am downloading files with ASP.NET Web Forms at a Linkbutton click event as follows:

var file = new FileInfo(filePath);

Response.Clear();
Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(file.Name));
Response.AddHeader("Content-Length", file.Length.ToString(CultureInfo.InvariantCulture));
Response.ContentType = "application/octet-stream";
Response.WriteFile(file.FullName);

The code works, but when the file is a .txt the same, in addition to its original content, comes with all the HTML of the current page. Someone knows how to solve this?

Answer 1

You are probably running some code even after writing the file in output.

Use the method Response.Flush to ensure the writing of the Stream reply, and then call Response.End to terminate at once with any subsequent code.

var file = new FileInfo(filePath);

Response.Clear();
Response.AddHeader("Content-Disposition", "attachment; filename="
                                          + HttpUtility.UrlEncode(file.Name));
Response.AddHeader("Content-Length", file.Length.ToString(CultureInfo.InvariantCulture));
Response.ContentType = "application/octet-stream";
Response.WriteFile(file.FullName);
Response.Flush();
Response.End();