//downloads file
public void ImageButtonDownload_Click(object sender, ImageClickEventArgs e)
{
int id = int.Parse(((System.Web.UI.WebControls.Image)(sender)).AlternateText);
Byte[] file = AudioFiles.Download(id);
System.Web.HttpContext context = System.Web.HttpContext.Current;
context.Response.Clear();
context.Response.ClearHeaders();
context.Response.ClearContent();
context.Response.AppendHeader("content-length", file.Length.ToString());
context.Response.ContentType = "audio/mpeg";
context.Response.AppendHeader("content-disposition", "attachment; filename=" + AudioFiles.GetFilenameById(id));
context.Response.BinaryWrite(file);
context.ApplicationInstance.CompleteRequest();
}