How to serialize on to existing file?

Question

Let say I have a file that contains a serialized object by BinaryFomatter. Now I want to be able to serialize another object and APPEND this on that existing file.

How can I do it?

Answer 1

This is indeed possible. The code below appends the object.

using (var fileStream = new FileStream("C:\file.dat", FileMode.Append))
{
    var bFormatter = new BinaryFormatter();
    bFormatter.Serialize(fileStream, objectToSerialize);
}

The following code de-serializes the objects.

var list = new List<ObjectToSerialize>();    

using (var fileStream = new FileStream("C:\file.dat", FileMode.Open))
{
    var bFormatter = new BinaryFormatter();
    while (fileStream.Position != fileStream.Length)
    {
         list.Add((ObjectToSerialize)bFormatter.Deserialize(fileStream));
    }
}

Note for this to work the file must only contain the same objects.