แก้ไข HTML ใน C#

using (Presentation pres = new Presentation())
{
    pres.Slides.RemoveAt(0); // removes default empty slide
    pres.Slides.AddFromHtml("page.html");

    AutoShape shape = (AutoShape)pres.Slides[0].Shapes[0];
    shape.TextFrame.Text = "New text";

    pres.Save("page.html", SaveFormat.Html);
}