Creating custom notification gateway classes

using System;
using System.Text;
using System.Data;
using System.Collections;
using System.Collections.Generic;
using System.Web;
using System.Web.UI;

using CMS.Notifications.Web.UI;
using CMS.Helpers;
using CMS.EventLog;
using CMS.SiteProvider;
using CMS.EmailEngine;
using CMS.DataEngine;

namespace EmailNotification
{
    /// <summary>
    /// Base class for e-mail notification gateway.
    /// </summary>
    public class EmailNotificationGateway : CMSNotificationGateway
    {
        /// <summary>
        /// Returns the e-mail gateway form.
        /// </summary>
        public override CMSNotificationGatewayForm GetNotificationGatewayForm()
        {
            try
            {
                Control ctrl = this.NotificationSubscriptionControl.Page.LoadControl("~/CorporateSite/EmailNotificationForm.ascx");
                ctrl.ID = ValidationHelper.GetIdentifier("notif" + this.NotificationGatewayObj.GatewayName);

                return (CMSNotificationGatewayForm)ctrl;
            }
            catch (Exception ex)
            {
                try
                {
                    // Logs exception events
                    EventLogProvider.LogException("EmailGateway", "EXCEPTION", ex);
                }
                catch
                {
                    // Unable to log the event
                }
            }
            return null;
        }

        /// <summary>
        /// Sends the notification via e-mail.
        /// </summary>
        public override void SendNotification()
        {
            try
            {
                if (this.NotificationSubscriptionObj != null)
                {
                    // Get template text
                    NotificationTemplateTextInfo templateText = NotificationTemplateTextInfoProvider.GetNotificationTemplateTextInfo(this.NotificationGatewayObj.GatewayID, this.NotificationSubscriptionObj.SubscriptionTemplateID);
                    if (templateText != null)
                    {
                        // Get the site name
                        string siteName = null;
                        SiteInfo si = SiteInfoProvider.GetSiteInfo(this.NotificationSubscriptionObj.SubscriptionSiteID);
                        if (si != null)
                        {
                            siteName = si.SiteName;
                        }

                        // Create message object
                        EmailMessage message = new EmailMessage();

                        // Get sender from settings
                        message.From = SettingsKeyInfoProvider.GetStringValue(siteName + ".CMSSendEmailNotificationsFrom");

                        // Do not send the e-mail if there is no sender specified
                        if (message.From != "")
                        {
                            // Initialize message
                            message.Recipients = this.NotificationSubscriptionObj.SubscriptionTarget;

                            // Body
                            if ((this.NotificationSubscriptionObj.SubscriptionUseHTML) &&
                                (this.NotificationGatewayObj.GatewaySupportsHTMLText) &&
                                (templateText.TemplateHTMLText != ""))
                            {
                                // HTML format, set Body property, resolve macros if possible
                                message.EmailFormat = EmailFormatEnum.Html;
                                if (this.Resolver != null)
                                {
                                    message.Body = this.Resolver.ResolveMacros(templateText.TemplateHTMLText);
                                }
                                else
                                {
                                    message.Body = templateText.TemplateHTMLText;
                                }
                            }
                            else
                            {
                                // Plaintext format, set PlainTextBody property, resolve macros if possible
                                message.EmailFormat = EmailFormatEnum.PlainText;
                                if (this.Resolver != null)
                                {
                                    message.PlainTextBody = this.Resolver.ResolveMacros(templateText.TemplatePlainText);
                                }
                                else
                                {
                                    message.PlainTextBody = templateText.TemplatePlainText;
                                }
                            }

                            // Subject, resolve macros if possible
                            if (this.Resolver != null)
                            {
                                message.Subject = this.Resolver.ResolveMacros(templateText.TemplateSubject);
                            }
                            else
                            {
                                message.Subject = templateText.TemplateSubject;
                            }

                            // Send email via Email engine API
                            EmailSender.SendEmail(siteName, message);
                        }
                    }
                }
            }
            catch (Exception ex)
            {
                try
                {
                     // Logs exception events
                     EventLogProvider.LogException("EmailGateway", "EXCEPTION", ex);
                }
                catch
                {
                    // Unable to log the event
                }
            }
        }
    }
}