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();

// Append new page to the document
Page page = document.AddPage(PageSizeType.A3, PageOrientationType.LandScape);

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

// Add standard font
uint font = document.AddFontStandard(StandardFontType.TimesRoman, FontEncodingType.WinAnsi);

// Set font size
double fontSize = 30;

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

// Set text position
double textX = 500.0f;
double textY = 280.0f;

// Draw Text
drawing.PlaceText(textX, textY, 0, "ComboBox");

// Closing drawing on the page
drawing.Close();

// Create new bounding rectangle
Rectangle rect = new Rectangle();

// Set position and size
rect.Left = 500;
rect.Bottom = 500;
rect.Top = 530;
rect.Right = 700;

// Create new combo box
ComboBoxControl comboBox = new ComboBoxControl(page, rect, "ComboBox1");

// Add items
comboBox.AddItem("Item1");
comboBox.AddItem("Item2");
comboBox.AddItem("Item3");

// Set border width
double borderWidth = 5.0f;

// Set border style
comboBox.SetBorderStyle(Drawing.RGBToColor(0, 0, 0), Drawing.RGBToColor(255, 255, 255), borderWidth);

// Set font size
fontSize = 25;

// Set font
comboBox.SetFont(font, fontSize, Drawing.RGBToColor(0, 0, 0));

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

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

Download example source code: bytescoutpdf_combobox.zip (4 KB)

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