MVC Controller Using Response Stream

Try returning one the FileResults: http://msdn.microsoft.com/en-us/library/system.web.mvc.fileresult.aspx

Also see this example: http://forums.asp.net/t/1491579.aspx/1

I have found one possible solution to this problem. You can simply define the action method to return an EmptyResult() and write directly to the response stream. For example:

public ActionResult RobotsText() {
    Response.ContentType = "text/plain";
    Response.Write("User-agent: *\r\nAllow: /");
    return new EmptyResult();
}

This seems to work without any problems. Not sure how 'MVC' it is...

I spent some time on the similar problem yesterday, and here's how to do it right way:

public ActionResult CreateReport()
{
    var reportData = MyGetDataFunction();
    var serverPipe = new AnonymousPipeServerStream(PipeDirection.Out);
    Task.Run(() => 
    {
        using (serverPipe)
        {
             MyWriteDataToFile(reportData, serverPipe)
        }
    });

    var clientPipe = new AnonymousPipeClientStream(PipeDirection.In,
             serverPipe.ClientSafePipeHandle);
    return new FileStreamResult(clientPipe, "text/csv");
}