For HTML2PDF and XML2PDF solution check our PDFDoc Scout ActiveX library instead

using System;
using System.Collections.Generic;
using System.Text;
using Bytescout.PDF;
using System.Diagnostics;

namespace HelloWorld
{
class Program
{
static void Main(string[] args)
{
// Create main PDF Doc Engine
PDFDocEngine engine = new PDFDocEngine("", "");

// Add new document
Document document = engine.AddDocument();

// font size constant
const int fontSize = 70;

//Add standart font
uint font = document.AddFontStandard(StandardFontType.TimesBold, FontEncodingType.WinAnsi);

// X position of the text to draw
int textX = 100;
// Y position of the text to draw
int textY = 100;

// Add standart page sizes
foreach (PageSizeType pageSize in Enum.GetValues(typeof(PageSizeType)))
{
// Append new standart size page to the document
Page page = document.AddPage(pageSize, PageOrientationType.LandScape);

//Create new drawing
Drawing drawing = page.AddDrawing();

// Set Active Font
drawing.SetActiveFont(font, fontSize, false, false);

// Draw Text
drawing.PlaceText(textX, textY, 0, pageSize.ToString());

// Close drawing
drawing.Close();
}

// Append new custom size page to the document
Page pageCustom = document.AddPage(800, 600);

//Create new drawing
Drawing drawingCustom = pageCustom.AddDrawing();

// Set Active Font
drawingCustom.SetActiveFont(font, fontSize, false, false);

// Draw Text
drawingCustom.PlaceText(textX, textY, 0, "Custom size: 800x600");

// Close drawing
drawingCustom.Close();

// Save document
document.Save("PageSize.pdf");

// open generated PDF document in default PDF viewer installed in Windows
Process.Start("PageSize.pdf");
}
}
}

Download example source code: bytescoutpdf_page_size.zip (10 KB)

For HTML2PDF and XML2PDF solution check our PDFDoc Scout ActiveX library instead