C# - Convert email to HTML¶

using System;
using System.Text.RegularExpressions;
using System.Text;
using System.IO;
using EAGetMail; //add EAGetMail namespace

namespace receiveemail
{
    class Program
    {
        static string _formatHtmlTag(string src)
        {
            src = src.Replace(">", ">");
            src = src.Replace("<", "&lt;");
            return src;
        }

        static string _formatAddresses(MailAddress[] addresses, string prefix)
        {
            if (addresses.Length == 0)
            {
                return "";
            }

            StringBuilder buffer = new StringBuilder();
            buffer.Append(string.Format("<b>{0}:</b> ", prefix));

            for (int i = 0; i < addresses.Length; i++)
            {
                buffer.Append(_formatHtmlTag(addresses[i].ToString()));
                if (i < addresses.Length - 1)
                {
                    buffer.Append("; ");
                }
            }

            buffer.Append("<br>");
            return buffer.ToString();
        }

        // We generate a html + attachment folder for every email, once the html is create,
        // next time we don't need to parse the email again.
        static void _generateHtmlForEmail(string emlFile, string htmlFile,
                            string attachmentFolder)
        {
            // For evaluation usage, please use "TryIt" as the license code, otherwise the
            //"invalid license code" exception will be thrown. However, the object will expire in 1-2 months, then
            //"trial version expired" exception will be thrown.
            Mail mail = new Mail("TryIt");
            mail.Load(emlFile, false);

            if (mail.IsEncrypted)
            {
                try
                {
                    // this email is encrypted, we decrypt it by user default certificate.
                    // you can also use specified certificate like this
                    // oCert = new Certificate();
                    // oCert.Load("c:\\test.pfx", "pfxpassword", Certificate.CertificateKeyLocation.CRYPT_USER_KEYSET)
                    // oMail = oMail.Decrypt( oCert );
                    mail = mail.Decrypt(null);
                }
                catch (Exception ep)
                {
                    Console.WriteLine(ep.Message);
                }
            }

            if (mail.IsSigned)
            {
                try
                {
                    // This email is digital signed.
                    Certificate signerCertificate = mail.VerifySignature();
                    Console.WriteLine("This email contains a valid digital signature.");

                    // You can add the certificate to your certificate storage like this
                    // cert.AddToStore( Certificate.CertificateStoreLocation.CERT_SYSTEM_STORE_CURRENT_USER,
                    //      "addressbook" );
                    // then you can use send the encrypted email back to this sender.
                }
                catch (Exception ep)
                {
                    Console.WriteLine(ep.Message);
                }
            }

            // Decode winmail.dat (Outlook TNEF stream) automatically.
            // also convert RTF body to HTML body automatically.MO
            mail.DecodeTNEF();

            string html = mail.HtmlBody;
            StringBuilder header = new StringBuilder();

            header.Append("<font face=\"Courier New,Arial\" size=2>");
            header.Append("<b>From:</b> " + _formatHtmlTag(mail.From.ToString()) + "<br>");

            header.Append(_formatAddresses(mail.To, "To"));
            header.Append(_formatAddresses(mail.Cc, "Cc"));

            header.Append(string.Format("<b>Subject:</b>{0}<br>\r\n", _formatHtmlTag(mail.Subject)));

            Attachment[] attachments = mail.Attachments;
            if (attachments.Length > 0)
            {
                if (!Directory.Exists(attachmentFolder))
                    Directory.CreateDirectory(attachmentFolder);

                header.Append("<b>Attachments:</b> ");
                for (int i = 0; i < attachments.Length; i++)
                {
                    Attachment attachment = attachments[i];

                    string attachmentName = string.Format("{0}\\{1}", attachmentFolder, attachment.Name);
                    attachment.SaveAs(attachmentName, true);

                    header.Append(string.Format("<a href=\"{0}\" target=\"_blank\">{1}</a> ",
                        attachmentName, attachment.Name));
                    if (attachment.ContentID.Length > 0)
                    {   // Show embedded image.
                        html = html.Replace("cid:" + attachment.ContentID, attachmentName);
                    }
                }
            }

            // Change original meta header encoding to utf-8
            Regex reg = new Regex("(<meta[^>]*charset[ \t]*=[ \t\"]*)([^<> \r\n\"]*)", RegexOptions.Multiline | RegexOptions.IgnoreCase);
            html = reg.Replace(html, "$1utf-8");
            if (!reg.IsMatch(html))
            {
                header.Insert(0, "<meta HTTP-EQUIV=\"Content-Type\" Content=\"text/html; charset=utf-8\">");
            }

            html = header.ToString() + "<hr>" + html;

            using (FileStream stream = new FileStream(htmlFile, FileMode.Create, FileAccess.Write, FileShare.None))
            {
                byte[] buffer = Encoding.UTF8.GetBytes(html);
                stream.Write(buffer, 0, buffer.Length);
                stream.Close();
            }
        }

        static void ConvertMailToHtml(string emlFile)
        {
            try
            {
                int pos = emlFile.LastIndexOf(".");
                string attachmentFolder = emlFile.Substring(0, pos);
                string htmlFile = attachmentFolder + ".htm";

                if (!File.Exists(htmlFile))
                {
                    // We haven't generate the html for this email, generate it now.
                    _generateHtmlForEmail(emlFile, htmlFile,attachmentFolder);
                }

                Console.WriteLine("Please open {0} to browse your email",
                    htmlFile);
            }
            catch (Exception ep)
            {
                Console.WriteLine(ep.Message);
            }
        }


        static void Main(string[] args)
        {
            ConvertMailToHtml("c:\\my folder\\test.eml");
        }
    }
}