DOTNet Sent Mail Coding

protected void SendMail(string FromUserName, string ToUserName, string strContent, string strSubject)
        {
            try
            {
                string mstrContents;
                //Retrives the contact mail ids
                if (FromUserName != null && FromUserName.Trim() != "" && ToUserName != null && ToUserName.Trim() != "")
                {
                    //Retrives the mailing contents

                    string strSiteName = DefaultSettings.SiteID;//ConfigurationManager.AppSettings["siteId"].ToString().Trim(); ;
                    SPSite site = new SPSite(strSiteName);
                    SPWeb web = site.OpenWeb();
                    string ToEmailid = web.AllUsers[ToUserName].Email;
                    string FromEmailId = ConfigurationManager.AppSettings["FromEmailId"].ToString().Trim(); ;
                    SmtpClient objSmtp = new SmtpClient(ConfigurationManager.AppSettings["SMTP"].ToString().Trim());


                    if (SPUtility.IsEmailServerSet(web))
                    {

                        MailAddress from = new MailAddress(FromEmailId);
                        MailAddress to = new MailAddress(ToEmailid);
                        MailMessage message = new MailMessage(from, to);
                        message.Subject = strSubject;
                        mstrContents = strContent;
                        message.Body = mstrContents;
                        objSmtp.Send(message);
                    }
                    site.Close();
                    site.Dispose();
                    web.Close();
                    web.Dispose();
                }
            }
            catch (Exception ex)
            {
                string strError = ex.Message.ToString();
                objErrorLog.WriteintoLogFile(ex.Message);
                objErrorLog.WriteintoLogFile(ex.StackTrace);
            }
        }