Custom SFE SendEmail Submit Action

CustomSendEmail.cs

using Sitecore.Diagnostics;
using Sitecore.ExperienceForms.Models;
using Sitecore.ExperienceForms.Mvc.Models.SubmitActions;
using Sitecore.ExperienceForms.Mvc.Processing.SubmitActions;
using Sitecore.ExperienceForms.Processing;
using Sitecore.Reflection;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Mail;
using System.Text;
using System.Threading.Tasks;

namespace KL.Extensions.SubmitActions
{
    public class CustomSendEmail : SendEmail
    {
        public CustomSendEmail(ISubmitActionData submitActionData) : base(submitActionData)
        {
        }
        protected override bool Execute(SendEmailData data, FormSubmitContext formSubmitContext)
        {
            Assert.ArgumentNotNull((object)formSubmitContext, nameof(formSubmitContext));
            using (MailMessage mailMessage = new MailMessage())
            {
                try
                {
                    CustomSendEmail.SetMessageAttributes(mailMessage, data, formSubmitContext);
                    this.MailSender.SendMail(mailMessage);
                    return true;
                }
                catch (Exception ex)
                {
                    this.Logger.LogError(ex.Message, ex, (object)this);
                    return false;
                }
            }
        }
        private static void SetMessageAttributes(
            MailMessage message,
            SendEmailData data,
            FormSubmitContext formSubmitContext)
        {
            Assert.ArgumentNotNull((object)message, nameof(message));
            message.From = new MailAddress(CustomSendEmail.ReplaceFieldValues(data.From, formSubmitContext));
            message.Subject = CustomSendEmail.ReplaceFieldValues(data.Subject, formSubmitContext);
            message.Body = CustomSendEmail.ReplaceFieldValues(data.Body, formSubmitContext);
            message.IsBodyHtml = true;
            CustomSendEmail.AddRecipients(message.To, CustomSendEmail.ReplaceFieldValues(data.To, formSubmitContext));
            CustomSendEmail.AddRecipients(message.CC, CustomSendEmail.ReplaceFieldValues(data.Cc, formSubmitContext));
            CustomSendEmail.AddRecipients(message.Bcc, CustomSendEmail.ReplaceFieldValues(data.Bcc, formSubmitContext));
        }

        private static string ReplaceFieldValues(string content, FormSubmitContext formSubmitContext)
        {
            string str = content;
            if (string.IsNullOrEmpty(str))
                return string.Empty;
            foreach (IViewModel field in (IEnumerable<IViewModel>)formSubmitContext.Fields)
                str = str.Replace(string.Format("{0}{1}{2}", (object)'[', (object)field.Name, (object)']'), CustomSendEmail.GetFieldValue(field));
            return str;
        }

        private static void AddRecipients(
          MailAddressCollection mailAddressCollection,
          string mailAddresses)
        {
            string str = mailAddresses;
            char[] chArray = new char[1] { ';' };
            foreach (string addresses in ((IEnumerable<string>)str.Split(chArray)).Select<string, string>((Func<string, string>)(p => p.Trim())).Where<string>((Func<string, bool>)(p => !string.IsNullOrEmpty(p))).ToArray<string>())
                mailAddressCollection.Add(addresses);
        }

        private static string GetFieldValue(IViewModel postedField)
        {
            Assert.ArgumentNotNull((object)postedField, nameof(postedField));
            try
            {
                return ReflectionUtil.CallMethod((object)postedField, "GetStringValue").ToString();
            }
            catch(InvalidOperationException)
            {
                return String.Empty;
            }
           
        }
    }
}