iTextSharp set document landscape (horizontal) A4

You can set the page size to a rotated A4. E.g. (assuming PDF, but should apply regardless):

iTextSharp.text.Document doc;

// ...initialize 'doc'...

// Set the page size
doc.SetPageSize(iTextSharp.text.PageSize.A4.Rotate());

I’ve done this with PDF without trouble, haven’t tried it with other doc types.