ASP.NET stream content from memory and not from file

Question

The users have requested the option to \"download\" a csv file representation of GridView contents. Does anyone know how to do this without saving the file to the server bu

Answer 1

Implement an IHttpHandler.

I used something similar to the following in the ProcessResponse for outputing a CSV that had previously been constructed in a database table...

public void ProcessRequest(HttpContext context)
{
    HttpResponse response = context.Response;
    HttpRequest request = context.Request;

    //Get data to output here...

    //Turn off Caching and enforce a content type that will prompt to download/save.
    response.AddHeader("Connection", "close");
    response.AddHeader("Cache-Control", "private");
    response.ContentType = "application/octect-stream";

    //Give the browser a hint at the name of the file.
    response.AddHeader("content-disposition", string.Format("attachment; filename={0}", _filename));

    //Output the CSV here...
    foreach(BatchDTO.BatchRecordsRow row in dtoBatch.BatchRecords)
        response.Output.WriteLine(row.Data);

    response.Flush();
    response.Close();
}

There are a number of libraries that make generating a CSV easier, you should just be able to pass it the Response.OutputStream to have it write to there rather than to a file stream.

Answer 2

Use context.Response.OutputStream.

Here's an example.

Answer 3

I created a StringBuilder and dump the contents to the Response object using the following code ("csv" is the StringBuilder variable).

    Response.ContentType = @"application/x-msdownload";
    Response.AppendHeader("content-disposition", "attachment; filename=" + FILE_NAME);

    Response.Write(csv.ToString());
    Response.Flush();
    Response.End();

Answer 4

I have used the RKLib export library a few times to great effect, this uses a memory stream and can be given any datatable which it will export as a csv download:

http://www.codeproject.com/KB/aspnet/ExportClassLibrary.aspx