The Art of SQL Server FILESTREAM - Red Gate Software

Chapter 4: FILESTREAM with Entity Framework and LINQ to SQL{using (SqlFileStream fs = new SqlFileStream(info.FilePath, info.Context, FileAccess.Read,FileOptions.WriteThrough, (long)info.Size)){fs.CopyTo(ms);}}}// TODO: Do some things with the memory stream,// or convert to byte array if serialization is required}tran.Commit();}}}}finally{if (OpenedConn) e.Connection.Close();}Listing 4-9:ReadItem method.This method first creates an Entity Framework object context (NorthPoleEntitiesclass) and retrieves the desired item. In this case, we used a lambda expression to indicatewhich item we are looking for. Lambda expressions may look a little intimidating, but thebasics can be learned easily. Here, we are indicating that, in the collection of all Items,we are looking for a single item that matches the predicate (think WHERE-clause) ItemID== ItemID, where the first ItemID is the scalar property and the second ItemID is theparameter value of the ReadItem function. We use the .SingleOrDefault() method toensure that if there is no item with the specified ItemID, the object context will return anull reference instead of throwing an exception.156