Export to CSV using MVC, C# and jQuery

I am trying to export a list to a CSV file. I got it all working up to the point I want to write to file to the response stream. This doesn't do anything.

Here is my code:

Call the the method from the page.

$('#btn_export').click(function () {
         $.post('NewsLetter/Export');
});

The code in the controller is as follows:

[HttpPost]
        public void Export()
        {
            try
            {
                var filter = Session[FilterSessionKey] != null ? Session[FilterSessionKey] as SubscriberFilter : new SubscriberFilter();

                var predicate = _subscriberService.BuildPredicate(filter);
                var compiledPredicate = predicate.Compile();
                var filterRecords = _subscriberService.GetSubscribersInGroup().Where(x => !x.IsDeleted).AsEnumerable().Where(compiledPredicate).GroupBy(s => s.Subscriber.EmailAddress).OrderBy(x => x.Key);

                ExportAsCSV(filterRecords);
            }
            catch (Exception exception)
            {
                Logger.WriteLog(LogLevel.Error, exception);
            }
        }

        private void ExportAsCSV(IEnumerable<IGrouping<String, SubscriberInGroup>> filterRecords)
        {
            var sw = new StringWriter();
            //write the header
            sw.WriteLine(String.Format("{0},{1},{2},{3}", CMSMessages.EmailAddress, CMSMessages.Gender, CMSMessages.FirstName, CMSMessages.LastName));

            //write every subscriber to the file
            var resourceManager = new ResourceManager(typeof(CMSMessages));
            foreach (var record in filterRecords.Select(x => x.First().Subscriber))
            {
                sw.WriteLine(String.Format("{0},{1},{2},{3}", record.EmailAddress, record.Gender.HasValue ? resourceManager.GetString(record.Gender.ToString()) : "", record.FirstName, record.LastName));
            }

            Response.Clear();
            Response.AddHeader("Content-Disposition", "attachment; filename=adressenbestand.csv");
            Response.ContentType = "text/csv";
            Response.Write(sw);
            Response.End();
        }

But after Response.Write(sw) nothing is happening. Is it even possible to save a file this way?

Regards

Edit
The response headers I see when I click the button are:

HTTP/1.1 200 OK
Cache-Control: private
Content-Type: text/csv; charset=utf-8
Server: Microsoft-IIS/7.5
X-AspNetMvc-Version: 2.0
Content-Disposition: attachment; filename=adressenbestand.csv
X-Powered-By: ASP.NET
Date: Wed, 12 Jan 2011 13:05:42 GMT
Content-Length: 113

Which seem OK to me..

Edit
I got rid of the jQuery part en replaced it by an hyperlink and this is working fine for me now:

<a class="export" href="NewsLetter/Export">exporteren</a>

yan.kun was on the right track but this is much much easier.

    public FileContentResult DownloadCSV()
    {
        string csv = "Charlie, Chaplin, Chuckles";
        return File(new System.Text.UTF8Encoding().GetBytes(csv), "text/csv", "Report123.csv");
    }

With MVC you can simply return a file like this:

public ActionResult ExportData()
{
    System.IO.FileInfo exportFile = //create your ExportFile
    return File(exportFile.FullName, "text/csv", string.Format("Export-{0}.csv", DateTime.Now.ToString("yyyyMMdd-HHmmss")));
}

In addition to Biff MaGriff's answer. To export the file using JQuery, redirect the user to a new page.

$('#btn_export').click(function () {
    window.location.href = 'NewsLetter/Export';
});

What happens if you get rid of the stringwriter:

        Response.Clear();
        Response.AddHeader("Content-Disposition", "attachment; filename=adressenbestand.csv");
        Response.ContentType = "text/csv";
        //write the header
        Response.Write(String.Format("{0},{1},{2},{3}", CMSMessages.EmailAddress, CMSMessages.Gender, CMSMessages.FirstName, CMSMessages.LastName));

        //write every subscriber to the file
        var resourceManager = new ResourceManager(typeof(CMSMessages));
        foreach (var record in filterRecords.Select(x => x.First().Subscriber))
        {
            Response.Write(String.Format("{0},{1},{2},{3}", record.EmailAddress, record.Gender.HasValue ? resourceManager.GetString(record.Gender.ToString()) : "", record.FirstName, record.LastName));
        }

        Response.End();

Respect to Biff, here's a few tweaks that let me use the method to bounce CSV from jQuery/Post against the server and come back as a CSV prompt to the user.

    [Themed(false)]
    public FileContentResult DownloadCSV()
    {
        
        var csvStringData = new StreamReader(Request.InputStream).ReadToEnd();

        csvStringData = Uri.UnescapeDataString(csvStringData.Replace("mydata=", ""));

        return File(new System.Text.UTF8Encoding().GetBytes(csvStringData), "text/csv", "report.csv");
    }

You'll need the unescape line if you are hitting this from a form with code like the following,

    var input = $("<input>").attr("type", "hidden").attr("name", "mydata").val(data);
    $('#downloadForm').append($(input));
    $("#downloadForm").submit();

From a button in view call .click(call some java script). From there call controller method by window.location.href = 'Controller/Method';

In controller either do the database call and get the datatable or call some method get the data from database table to a datatable and then do following,

using (DataTable dt = new DataTable())
                        {
                            sda.Fill(dt);
                            //Build the CSV file data as a Comma separated string.
                            string csv = string.Empty;
                            foreach (DataColumn column in dt.Columns)
                            {
                                //Add the Header row for CSV file.
                                csv += column.ColumnName + ',';
                            }
                            //Add new line.
                            csv += "\r\n";
                            foreach (DataRow row in dt.Rows)
                            {
                                foreach (DataColumn column in dt.Columns)
                                {
                                    //Add the Data rows.
                                    csv += row[column.ColumnName].ToString().Replace(",", ";") + ',';
                                }
                                //Add new line.
                                csv += "\r\n";
                             }
                             //Download the CSV file.
                             Response.Clear();
                             Response.Buffer = true;
                             Response.AddHeader("content-disposition", "attachment;filename=SqlExport"+DateTime.Now+".csv");
                             Response.Charset = "";
                             //Response.ContentType = "application/text";
                             Response.ContentType = "application/x-msexcel";
                             Response.Output.Write(csv);
                             Response.Flush();
                             Response.End();
                           }

Even if you have resolved your issue, here is another one try to export csv using mvc.

return new FileStreamResult(fileStream, "text/csv") { FileDownloadName = fileDownloadName };

I Think you have forgot to use

  Response.Flush();

under

  Response.Write(sw);

please check

  public FileContentResult DownloadCSV()
    {
        return File(new System.Text.UTF8Encoding().GetBytes("Ram, Saran, Raja"), "text/csv", "downloadFileName.csv");
    }