public Stream GetBookPhoto(string isbn)
{
// Throw exception if isbn is not present
if (isbn == null)
{
throw new Exception("Isbn not supplied");
}
// Get path to the data source
string path = string.Format("{0}..\\..\\..\\Photos",
HostingEnvironment.ApplicationPhysicalPath);
// Return book photo
return(BookInfo.GetBookPhoto(isbn, path));
}