using iTextSharp.text;
using iTextSharp.text.pdf;
using iTextSharp.tool.xml;


byte[] pdf; // result will be here

var cssText = File.ReadAllText(MapPath("~/css/test.css"));
var html = File.ReadAllText(MapPath("~/css/test.html"));

using (var memoryStream = new MemoryStream())
{
        var document = new Document(PageSize.A4, 50, 50, 60, 60);
        var writer = PdfWriter.GetInstance(document, memoryStream);
        document.Open();

        using (var cssMemoryStream = new MemoryStream(System.Text.Encoding.UTF8.GetBytes(cssText)))
        {
            using (var htmlMemoryStream = new MemoryStream(System.Text.Encoding.UTF8.GetBytes(html)))
            {
                XMLWorkerHelper.GetInstance().ParseXHtml(writer, document, htmlMemoryStream, cssMemoryStream);
            }
        }

        document.Close();

        pdf = memoryStream.ToArray();
}