I have a button that exports data from telerik's RadGrid into an Excel document.
However, I am encountering the following error when I attempt to export:
[System.Threading.ThreadAbortException]:
{Unable to evaluate expression because the code is optimized or a native frame is on top of the call stack.}
Here's my code:
private void GenerateFile(object structure, string fileName)
{
Workbook workbook = structure as Workbook;
var formatProvider = new XlsxFormatProvider();
try
{
using (MemoryTributary ms = new MemoryTributary())
{
Response.ClearHeaders();
Response.ClearContent();
Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
Response.AddHeader("content-disposition", "attachment; filename=" + fileName);
formatProvider.Export(workbook, ms);
ms.Position = 0;
ms.WriteTo(Response.OutputStream);
Response.End();
}
}
catch (System.OutOfMemoryException ex)
{
}
}
}
I have tried the following solutions based on posts I have found online that dealt with the same issue, none of the solutions have worked:
Change "Response.End()" to "HttpContext.Current.ApplicationInstance.CompleteRequest()"
Change "Response.End()" to "HttpContext.Current.Response.End()"
Move "Response.End()" inside a finally block.
Move "Response.End()" outside of the try-catch scope.
None of the above solutions have solved the issue. Any further advice on how to resolve this error is greatly appreciate it.
Thanks.
You are causing the exception by calling Response.End. End's documented behavior is to flush buffers and abort the current request immediately by aborting it. It's not used in .NET programming. It's there only for compatibility with old ASP code.
Just remove Response.End() from your code
You should also remove the catch statement. Exceptions should be investigated and fixed, not covered up. An OutOfMemoryException means that there is something seriously wrong with the code that's causing leaks. It can be caused either because you run out of memory or because memory is so fragmented that .NET is unable to allocate a large enough block
Related
I am creating a docx file with my app, and I get stuck with the Response.End(). I get this error:
Thread was being aborted
I get this error, but the file is still created anyway. When I try to open the file it's always corrupted. I am not having any success writing the .docx file. Please let me know what I am doing wrong.
HttpContext.Current.Response.ContentType = "application/vnd.openxmlformats-officedocument.wordprocessingml.document; charset=utf-8";
HttpContext.Current.Response.AddHeader("content-disposition", String.Format("attachment;filename={0}", "mydoc.docx"));
HttpContext.Current.Response.BinaryWrite(ourString);
HttpContext.Current.Response.Flush();
HttpContext.Current.Response.End();
Note, you should not place Response.End inside the try-catch block because it's expected that it will throw that exception.
See the HttpResponse.End method's remarks:
To mimic the behavior of the End method in ASP, this method tries to
raise a ThreadAbortException exception.
You can avoid this by using the following:
var response = HttpContext.Current.Response;
response.Clear();
response.ContentType = "application/vnd.openxmlformats-officedocument.wordprocessingml.document;
response.AddHeader("Content-Disposition", "attachment;filename=mydoc.docx");
response.OutputStream.Write(ourString, 0, ourString.Length);
response.Flush();
HttpContext.Current.ApplicationInstance.CompleteRequest();
Note, in the above code I'm presuming that your ourString variable is byte array because you were passing it to the BinaryWrite method in your snippet code.
However, this name leads me to believe that you have just converted your string to byte[], is that correct?
If it is, note that this is not a valid DOCX file, DOCX format is not a plain text, you need to write it correctly using Office Open XML format (WordprocessingML).
I have a code set that runs on the server, which correctly generates a zip file and stores it on the server. I have that file location as a physical path.
Nothing I have attempted has allowed me to use the response to the client to download that file.
Attempt 1:
System.IO.FileInfo fi = new System.IO.FileInfo(zipFilePath);
//setup HTML Download of provided Zip.
//application/zip
Response.ClearContent();
Response.Clear();
Response.ClearHeaders();
Response.Buffer = true;
Response.ContentType = "application / zip";
Response.AddHeader("Content-Disposition",
"attachment; filename=\"" + System.IO.Path.GetFileName(zipFilePath) + "\";");
Response.AddHeader("Content-Length", fi.Length.ToString());
Response.TransmitFile(zipFilePath);
Response.Flush();
Response.End();
No result. Code executes without error but there is no download to the client.
Attempt 2:
//Almost the same as attempt 1, but with WriteFile instead
Response.WriteFile(zipFilePath);
No Result, same as Attempt 1.
Attempt 3:
//Note: Same Header Section as Attempts 1 and 2
System.IO.BinaryReader reader = new System.IO.BinaryReader(new System.IO.FileStream(zipFilePath, System.IO.FileMode.Open));
int CHUNK = 1024;
List<byte> FileArray = new List<byte>();
while (reader.BaseStream.Position < reader.BaseStream.Length)
FileArray.AddRange(reader.ReadBytes(CHUNK));
byte[] bArray = FileArray.ToArray();
reader.Close();
Response.OutputStream.Write(bArray, 0, bArray.Length);
Response.Flush();
Response.End();
No Result, Same as previous attempts
Attempt 4:
//Identical to Attempt 3, but using BinaryWrite
Response.BinaryWrite(bArray);
No Result, Same as previous Attempts.
The Question
Every one of these code blocks runs with no error, But The Save File dialog NEVER appears. I get nothing at all. I cannot figure out for the life of me what I might be missing.
The File Path has been verified as correct
The Code is running on the server, not on the client, I cannot use the 'WebClient.Download' method for this reason
If anyone has any suggestions, I'm all ears. I have no idea how to get this file to download to the client.
I tested your code (attempt 1) and got it working fine with a test file. If the file path would be wrong, you'd get an System.IO.FileNotFoundException so that's probably not the issue.
A couple of ways to address this:
Try inspecting the webpage in, for example, Chrome by right-clicking
and choose inspect. Then click on Network tab, and refresh the
page (where you're supposed to get the file). Check the response
headers for that request - what is it?
Try setting content-type to application/octet-stream
Use debugger in Visual Studio and step through.
This turned out to be an Ajax related error causing issues between UpdatePanels and POST Responses.
The issue was fixed on the page load of the page by adding the call
ScriptManager.GetCurrent(Page).RegisterPostBackControl(btnGenerate);
In my page i am trying to download file. THe file is downloaded successfully but i get System.Threading.ThreadAbortException. So i handled that in my try Catch Block and set the error lable to blank but it doesnt get updated in page.
catch (System.Threading.ThreadAbortException)
{
lblErrorMsg.Text = "dfdf";
}
catch (Exception ex)
{
lblErrorMsg.Text = "Error while processing you request :<br> Erorr Description : " + ex.Message;
}
This is my Write file function
public static void WriteFile(string nameOfFile, string fileContent, HttpResponse writer)
{
writer.ClearHeaders();
writer.ClearContent();
writer.ContentType = "text/xml";
writer.AppendHeader("Content-Disposition", "attachment; filename=" + nameOfFile);
writer.Write(fileContent);
writer.Flush();
writer.End();
}
Can someone tell why label is not set to blank even though it comes under the Catch Block of system.thread.threadabortexceptiopn when i debug code ?
ThreadAbortException happens because you close the Response prematurely, by calling End() method of Response object.
This also explains why it's too late to write on the page content. It's not a very annoying error but it would be better to handle it cleanly.
Just check these answers Why Response.Redirect causes System.Threading.ThreadAbortException? or How to Avoid Response.End() "Thread was being aborted" Exception during the Excel file download and other answers related to Response and ThreadAbortException to understand it and handle properly by writing a better code for file download, according your usage.
Also please note that doesn't make a great sense to have both a completely rewritten Response stream for a page and some content on it, like a Label.
I am writing large CSV files to the Response with Response.BufferOutput set to false. This is because the file has the potential to take a long time to download so the user can see some progress. I generate a line for the CSV from a object and write to the response using Response.Write().
This works well however if there is an unexpected error after the Response has started writing then the client will receive a file with only part of the data and could be missing lots of lines but they might not realise it.
Is there a way to somehow cancel the file download without buffering all the content? Could there be some way to indicate that the response is invalid so the browser disregards the file?
Code below shows the main idea of my code
public void StreamCsvFile(string fileName,List<myObject> myObjectList)
{
Response.Clear();
Response.ContentType = "text/csv";
Response.AddHeader("content-disposition", "filename=" + fileName);
Response.BufferOutput = false;
string headerLine = GetHeaderLine();
Response.Write(headerLine)
try
{
foreach(var myObject in myObjectList)
{
string line = myObject.ToCsvString();
Response.Write("\n" + line);
}
}
finally
{
Response.End();
}
}
Write to a temporary file first.
Set the content-length on the response.
Use Response.TransmitFile to send this temp file.
Browsers will reject download if content length doesn't match.
I'm trying to create a file handler for users to download files when their filenames are clicked on a web page. I've implemented this a few times without issues, but I'm currently getting an error which I can't get my head around.
Code:
protected void btnViewFile_Click(object sender, EventArgs e)
{
var btnViewFile = sender as LinkButton;
Response.Clear();
Response.ContentType = "application/octet-stream";
Response.AppendHeader("Content-Disposition", "attachment; filename=" + btnViewFile.CommandArgument.ToString());
Response.WriteFile(Server.MapPath(btnViewFile.CommandArgument));
Response.End();
}
If I look at the browser console, I can see:
Uncaught Sys.WebForms.PageRequestManagerParserErrorException: Sys.WebForms.PageRequestManagerParserErrorException: The message received from the server could not be parsed.
No exceptions appear to be thrown in the code, the requested file is converted into the correct full path; and I've tried quite a few different things - clearing headers manually, flushing before ending, giving a more explicit content-type header, using AddHeader instead of AppendHeader, using TransmitFile rather than WriteFile, and quite a bit more.
Any ideas?
In case anyone else comes across this situation, the problem was that I was registering it as a postback control in ScriptManager, not an async postback control.
D'oh!