[c#] Find size of object instance in bytes in c#

You may be able to approximate the size by pretending to serializing it with a binary serializer (but routing the output to oblivion) if you're working with serializable objects.

class Program
{
    static void Main(string[] args)
    {
        A parent;
        parent = new A(1, "Mike");
        parent.AddChild("Greg");
        parent.AddChild("Peter");
        parent.AddChild("Bobby");

        System.Runtime.Serialization.Formatters.Binary.BinaryFormatter bf =
           new System.Runtime.Serialization.Formatters.Binary.BinaryFormatter();
        SerializationSizer ss = new SerializationSizer();
        bf.Serialize(ss, parent);
        Console.WriteLine("Size of serialized object is {0}", ss.Length);
    }
}

[Serializable()]
class A
{
    int id;
    string name;
    List<B> children;
    public A(int id, string name)
    {
        this.id = id;
        this.name = name;
        children = new List<B>();
    }

    public B AddChild(string name)
    {
        B newItem = new B(this, name);
        children.Add(newItem);
        return newItem;
    }
}

[Serializable()]
class B
{
    A parent;
    string name;
    public B(A parent, string name)
    {
        this.parent = parent;
        this.name = name;
    }
}

class SerializationSizer : System.IO.Stream
{
    private int totalSize;
    public override void Write(byte[] buffer, int offset, int count)
    {
        this.totalSize += count;
    }

    public override bool CanRead
    {
        get { return false; }
    }

    public override bool CanSeek
    {
        get { return false; }
    }

    public override bool CanWrite
    {
        get { return true; }
    }

    public override void Flush()
    {
        // Nothing to do
    }

    public override long Length
    {
        get { return totalSize; }
    }

    public override long Position
    {
        get
        {
            throw new NotImplementedException();
        }
        set
        {
            throw new NotImplementedException();
        }
    }

    public override int Read(byte[] buffer, int offset, int count)
    {
        throw new NotImplementedException();
    }

    public override long Seek(long offset, System.IO.SeekOrigin origin)
    {
        throw new NotImplementedException();
    }

    public override void SetLength(long value)
    {
        throw new NotImplementedException();
    }
}