public interface IEmailGenerator
{
    MailMessage generateEmail(IMailObject mailObject, string htmlTemplate, string textTemplate);
}

public class EmailGenerator : IEmailGenerator, IRegisterInIoC
{
    private string mergeTemplate(string template, object obj)
    {
        Regex operationParser = new Regex(@"$(?:(?<operation>[w-,.]+)x20)(?<value>[w-,.]+)$", RegexOptions.Compiled);
        Regex valueParser = new Regex(@"$(?<value>[w-,.]+)$", RegexOptions.Compiled);

        var operationMatches = operationParser.Matches(template).Cast<Match>().Reverse().ToList();
        foreach (var match in operationMatches)
        {
            string operation = match.Groups["operation"].Value;
            string value = match.Groups["value"].Value;
            var propertyInfo = obj.GetType().GetProperty(value);
            if (propertyInfo == null)
                throw new TillitException(String.Format("Could not find '{0}' in object of type '{1}'.", value, obj));

            object dataValue = propertyInfo.GetValue(obj, null);

            if (operation == "endforeach")
            {
                string foreachToken = "$foreach " + value + "$";
                var startIndex = template.LastIndexOf(foreachToken, match.Index);
                var templateBlock = template.Substring(startIndex + foreachToken.Length, match.Index - startIndex - foreachToken.Length);
                var items = (IEnumerable) value;

                string blockResult = "";

                foreach (object item in items)
                {
                    blockResult += mergeTemplate(templateBlock, item);
                }

                template = template.Remove(startIndex, match.Index - startIndex).Insert(startIndex, blockResult);
            }
        }

        var valueMatches = valueParser.Matches(template).Cast<Match>().Reverse().ToList();
        foreach (var match in valueMatches)
        {
            string value = match.Groups["value"].Value;
            var propertyInfo = obj.GetType().GetProperty(value);
            if (propertyInfo == null)
                throw new Exception(String.Format("Could not find '{0}' in object of type '{1}'.", value, obj));

            object dataValue = propertyInfo.GetValue(obj, null);

            template = template.Remove(match.Index, match.Length).Insert(match.Index, dataValue.ToString());
        }

        return template;
    }

    public MailMessage generateEmail(IMailObject mailObject, string htmlTemplate, string textTemplate)
    {
        var mailMessage = new MailMessage();
        mailMessage.IsBodyHtml = true;
        mailMessage.Subject = mailObject.Subject;
        mailMessage.BodyEncoding = Encoding.UTF8;

        // Create the Plain Text version of the email
        mailMessage.Body = this.mergeTemplate(textTemplate, mailObject);

        // Create the HTML version of the email
        ContentType mimeType = new System.Net.Mime.ContentType("text/html");

        AlternateView alternate = AlternateView.CreateAlternateViewFromString(this.mergeTemplate(htmlTemplate, mailObject), mimeType);
        mailMessage.AlternateViews.Add(alternate);

        return mailMessage;
    }
}

public class MessageData : IMailObject
{
    public string Property1 { get; private set; }
    public string Property2 { get; private set; }
    public string Property3 { get; private set; }
    public string Property4 { get; private set; }
    public string Property5 { get; private set; }
    public string Property6 { get; private set; }
    public string Subject
    {
        get { return this.Property1 + DateTime.Now.ToShortDateString(); }
    }
    public List<MessageItemData> Items { get; private set; }

    public MessageData(string property1, string property2, string property3, DateTime property4, string property7, string property8, DateTime property9, DateTime property10, int property11, double property12, string property5, string property6)
    {
        this.Property1 = property1;
        this.Property2 = property2;
        this.Property3 = property3;
        this.Property4 = property4.ToShortDateString();
        this.Property5 = property5;
        this.Property6 = property6;

        this.Items = new List<MessageItemData>();
        this.Items.Add(new MessageItemData(property7, property8, property9, property10, property11, property12));
    }
}

public class MessageItemData
{
    public string Property7 { get; private set; }
    public string Property8 { get; private set; }
    public string Property9 { get; private set; }
    public string Property10 { get; private set; }
    public int Property11 { get; private set; }
    public double Property12 { get; private set; }

    public MessageItemData( string property7, string property8, DateTime property9, DateTime property10, int property11, double property12)
    {
        this.Property7 = property7;
        this.Property8 = property8;
        this.Property9 = property9.ToShortDateString();
        this.Property10 = property10.ToShortDateString();
        this.Property11 = property11;
        this.Property12 = property12;
    }
}