MailgunMessage.cs

using System.Net;
using System.Net.Mail;

namespace Client.Project.Messaging
{
	/// <summary>
	/// 	Provides a message object that sends the email through gmail. 
	/// 	MailgunMessage is inherited from <c>System.Web.Mail.MailMessage</c>, so all the mail message features are available.
	/// </summary>
	public class MailgunMessage : MailMessage
	{
		#region Fields

		private const string _smtpHost = "smtp.mailgun.org";
		private const string _smtpPass = "PUT_PASSWORD_HERE";
		private const int _smtpPort = 587;
		private const string _smtpUser = "[email protected]";
		private readonly MailAddress _mailAddress = new MailAddress("FROM ADDRESS", "FROM NAME");
		private readonly SmtpClient _smtpClient = new SmtpClient();

		#endregion

		#region .ctor

		public MailgunMessage(string toEmail, string subject, string body, bool isBodyHtml) : this()
		{
			To.Add(toEmail);
			From = _mailAddress;
			Subject = subject;
			Body = body;
			IsBodyHtml = isBodyHtml;
		}

		private MailgunMessage()
		{
			_smtpClient.Host = _smtpHost;
			_smtpClient.Port = _smtpPort;
			_smtpClient.EnableSsl = true;
			_smtpClient.UseDefaultCredentials = false;
			var cred = new NetworkCredential(_smtpUser, _smtpPass);
			_smtpClient.Credentials = cred;
		}

		#endregion

		#region Methods

		public void Send()
		{
			try
			{
				_smtpClient.Send(this);
			}
			catch (SmtpException ex)
			{
				Log<MailgunMessage>.Logger.Fatal("Email sending faliure - SMTP", ex);
			}
			catch (WebException ex)
			{
				Log<MailgunMessage>.Logger.Fatal("Email sending failure - WebException", ex);
			}
		}

		#endregion
	}
}

Usage.cs

public static void SendEmail(string toEmail, string subject, string body, bool isBodyHtml)
		{
			var message = new MailgunMessage(toEmail, subject, body, isBodyHtml);
			message.Send();
		}