I am trying the following, as seen here on SO:
System.Web.HttpResponse response = System.Web.HttpContext.Current.Response;
response.ClearContent();
response.Clear();
response.ContentType = "video/mp4";
response.AddHeader("Content-Type", "video/mp4");
response.AddHeader("Content-Disposition", "attachment; filename=" + filename + "; ");
response.WriteFile(sourcepath + filename);
response.End();
But no dialog opens and I have no idea where it saves the file.
Thanks