File is empty and I don't understand why. Asp.net mvc FileResult

问题

I am trying to use the built in asp.net file result to return a file that I am trying to make through a file stream. I am using Dday.ical to make my calendar for export

    MemoryStream export = new MemoryStream();         
    iCalendarSerializer serializer = new iCalendarSerializer(iCal);
    serializer.Serialize(export,System.Text.Encoding.Default);
    return export;

Here is my actionResult

public ActionResult ExportCalendar()
{
    string userName = User.Identity.Name;
    Guid userId = membershipS.GetUsersId(userName);
    var calendarStream = calendarS.ExportCalendar(userId);
    return File(calendarStream, "text/calendar", "test.ics");       
}

When I download the file it is 0bytes.

回答1:

Try resetting the stream's position:

calendarStream.Position = 0;

That way when the FileResult starts reading from the stream it will read it from the beginning instead of from the end (after which there are obviously no more bytes!).

来源：https://stackoverflow.com/questions/2032196/file-is-empty-and-i-dont-understand-why-asp-net-mvc-fileresult