Demonstration of things you can do with inner classes

Presentation.cs

    public class Presentation
    {
        public class PackageResult
        {
            public string Name;
            public Stream Stream;
        }
        //PackageResult as an inner clas can be a good idea since its really just a Tuple and has no reusability value
        public PackageResult Package()
        {
	 //...
	}
    }

PresentationTemplate.cs

    public class PresentationTemplate 
    {
        public string Id { get; private set; }
        public IEnumerable<PresentationTemplate.Slide> Slides { get; private set; }
        private readonly FileInfo templateFile;
        protected virtual PresentationTemplate.Slide CreateSlide(CM.Slide s, PresentationExporter exporter, CM.Presentation preso)
        {
            return new PresentationTemplate.Slide(
                             this,
                            Int32.Parse(s.Id),
                            () => exporter.Export(preso, s)
                        );
        }


        public class Slide
        {
            public string Id { get; private set; }
            
            public void DoStuff()
            {
                //Note that this also has access to the internals of its parent
                doStuffWith(this.Template.templateFile)
            }
            public Slide(PresentationTemplate vpt, int originalSlideId, Func<XDocument> getSvg)
            {
                this.Template = vpt;
                this.OriginalSlideId = originalSlideId;
                this.Id = SlideDelimitorUtils.AssembleSlideId(vpt.Id, originalSlideId);
                this.getSvg = getSvg;
            }
        }
    }