How to create file of files?

Question

class Node
{
    FooType Data; // I can save Data to file with extension .foo
    void Save()
    {
       // save Data to .foo file
    }
}

Now ,

class Graph
{
    List<Node> Nodes; 
    void Save()
    {
        foreach(Node node in Nodes)
        {
            node.Save();
        }
    }
}

Now when I invoke someGraph.Save(); then it creates Nodes.Count number of files.

I would like to appear those files as one file with extension somename.graph and be able to read it again as Nodes.

How can I do this? Is there a way to bundle files into a single different file?

Answer 1

Use an archive format like zip.

Without external library support, you could just use .Net's serialisation mechanism to store a Dictionary<string, byte[]> (filename and data for each file) in a single file. Start here.

Answer 2

Or Graph.Save should pass the file stream it is using to each of the node.Save calls, so Node.Save uses the same file stream as its enclosing Graph.

Answer 3

Can you not use the classes in the System.IO.Compression namespace? Specifically, GZipStream? This would not constitute a 3rd party library as it is built into .Net and is available from 2.0 and onward.