As I understood from the comments, you need automatic hierarchical numeration of multilevel list in PDF. iTextSharp doesn't calculate level's numeration automatically, but I found the library, which does. It's called PDFFlow. You only need to set level to every item and set hierarchical numeration to "true":
using Gehtsoft.PDFFlow.Builder;
var latin = NumerationStyle.LowerLatin;
var arabic = NumerationStyle.Arabic;
DocumentBuilder.New().AddSection()
.AddParagraph("Level 0, Item 1")
.SetListNumbered().ToSection()
.AddParagraph("Level 1, Item a")
.SetListNumbered(latin, 1, hierarchicNumeration: true).ToSection()
.AddParagraph("Level 1, Item b")
.SetListNumbered(latin, 1, hierarchicNumeration: true).ToSection()
.AddParagraph("Level 0, Item 2")
.SetListNumbered().ToSection()
.AddParagraph("Level 1, Item 1")
.SetListNumbered(arabic, 1, hierarchicNumeration: true).ToSection()
.AddParagraph("Level 1, Item 2")
.SetListNumbered(arabic, 1, hierarchicNumeration: true).ToSection()
.AddParagraph("Level 0, Item 3")
.SetListNumbered().ToSection()
.AddParagraph("Level 1, Item 1")
.SetListNumbered(arabic, 1, hierarchicNumeration: true).ToSection()
.AddParagraph("Level 1, Item 2")
.SetListNumbered(arabic, 1, hierarchicNumeration: true).ToSection()
.AddParagraph("Level 2, Item 1")
.SetListNumbered(arabic, 2, hierarchicNumeration: true).ToSection()
.AddParagraph("Level 2, Item 2")
.SetListNumbered(arabic, 2, hierarchicNumeration: true).ToSection()
.AddParagraph("Level 1, Item 3")
.SetListNumbered(arabic, 1, hierarchicNumeration: true).ToDocument()
.Build("Result.pdf");
The above code will generate the following:
Multilevel list with hierarchic numeration in PDF.
Hope, this will help you.