How to download xml file in asp.net using C#

 If you return FileResult it will be file, if you return string it will be open in browser.

Update: This code will return file for downloading

public FileResult GetXmlFile()
{
    string xml=""; //string presented xml
    var stream = new MemoryStream();
    var writer = XmlWriter.Create(stream);
    writer.WriteRaw(xml);
    stream.Position = 0;
    var fileStreamResult = File(stream, "application/octet-stream", "xml.xml");
    return fileStreamResult;        
}