public void UpdateMailTemplateHeader(MailTemplateHeader header)
        {
            var dbHeader = _mailTemplateHeaders.FirstOrDefault(c => c.MailTemplateHeaderId == header.MailTemplateHeaderId);

            header.CreationDate = dbHeader.CreationDate;
            header.CreationUser = dbHeader.CreationUser;
            _mailTemplateHeaders.Remove(dbHeader);
            _mailTemplateHeaders.Add(header);

            SaveData();
        }
        public void CreateMailTemplateHeader(MailTemplateHeader header)
        {
            _mailTemplateHeaders.Add(header);

            SaveData();
        }