Call IXDocument::OpenStream method to access the 3rd party stream. Pass the access parameter to read or write stream.

Use this approach when it is required to store a single structure at the model.

Stream Access Handler

To simplify the handling of the stream lifecycle, use the Documents Manager API from the SwEx.AddIn framework:

private void HandleStream(ISwDocument doc)
{
    doc.StreamReadAvailable += OnStreamReadAvailable;
    doc.StreamWriteAvailable += OnStreamWriteAvailable;
}

private void OnStreamWriteAvailable(IXDocument doc)
{
    SaveToStream(doc as ISwDocument);
}

private void OnStreamReadAvailable(IXDocument doc)
{
    LoadFromStream(doc as ISwDocument);
}

Reading data

IXDocument::OpenStream method throws an exception when storage does not exist. Use IXDocument::TryOpenStream extension method which returns null for the storage which not exists on reading.

private void LoadFromStream(ISwDocument model)
{
    using (var str = model.TryOpenStream(STREAM_NAME, AccessType_e.Read))
    {
        if (str != null)
        {
            var xmlSer = new XmlSerializer(typeof(StreamData));
            m_StreamData = xmlSer.Deserialize(str) as StreamData;
        }
    }
}

Writing data

IXDocument::OpenStream will always return the pointer to the stream (stream is automatically created if it doesn't exist).

private void SaveToStream(ISwDocument model)
{
    using (var str = model.OpenStream(STREAM_NAME, AccessType_e.Write))
    {
        var xmlSer = new XmlSerializer(typeof(StreamData));
        xmlSer.Serialize(str, m_StreamData);
    }
}