sendgrid send to List of emails from C# Winform App

Question

I have a Winform app that I would like to send an email out from, I am able to do so using sendgrid and typed in email addresses. the problem is the the emails I want to send will go to different people depending on the situation, so the "to field" needs to be dynamic.

I have an SQL database that stores email address for events that people want to be notified of, I pull that list up when getting ready to send the email but I cannot figure out how to get those items into the list of <EmailAddress> that Sendgrid wants.

            try
        {
            using (SqlConnection conn = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["MfgDataCollector"].ToString()))
            {
                var apiKey = "SendGrid Key";
                var client = new SendGridClient(apiKey);
                var from = new EmailAddress("test@gmail.com", "test from App");

                //Standard Email lists
                //var tos = new List<EmailAddress>
                //{
                //new EmailAddress("test@gmail.com"),
                //new EmailAddress("test2@gmail.com")
                //};

                //Query to get emails from SQL using Dapper
                DynamicParameters param = new DynamicParameters();
                param.Add("@Zone", Variables.Zone);
                param.Add("@Gatelevel", Lbl_GateLevel.Text);
                List<AlertMessages> EmailList = conn.Query<AlertMessages>("GetEmailList", param, commandType: CommandType.StoredProcedure).ToList<AlertMessages>();

                //Lost here??? Not sure how to get EmailList to EmailAddresses 
                var tos = new List<EmailAddress> { };

                string subject = txt_Subject.Text;
                string plainTextContent = txt_Body.Text;
                var htmlContent = txt_Body.Text;
                var showAllRecipients = true; // Set to true if you want the recipients to see each others email addresses

                var msg = MailHelper.CreateSingleEmailToMultipleRecipients(from,
                                                                           tos,
                                                                           subject,
                                                                           plainTextContent,
                                                                           htmlContent,
                                                                           showAllRecipients
                                                                           );
                var response = await client.SendEmailAsync(msg);
                MessageBox.Show("SendGrid Completed");
            }
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message, "Send Email Notification - SendGrid - Oops!", MessageBoxButtons.OK, MessageBoxIcon.Error);
        }

Alert Messages Class

public class AlertMessages
    {
        public int ID { get; set; }
        public string EmailAddress { get; set; }
        public int ZoneID { get; set; }
        public string Zone { get; set; }
        public string GateLevel { get; set; }
        public string Emails { get; set; }
    }

Answer 1

Assuming that you are successfully getting list of email from your Dapper query

List<AlertMessages> EmailList = conn.Query<AlertMessages>("GetEmailList", param, commandType: CommandType.StoredProcedure).ToList<AlertMessages>();

And your AlertMessages class have string properties are Email and Name like

class AlertMessages
{
    ...
    public string Email { get; set; }
    public string Name { get; set; }
    ...
}

Then you can flatten your List<AlertMessages> to List<EmailAddress> like,

var tos = EmailList.Select(item => new EmailAddress { Email = item.Email, Name = item.Name }).ToList();

Where item is a select iterator variable of type of AlertMessagesand item.Email and item.Name are the properties of respective iterator variable.

And then pass the above tos list to CreateSingleEmailToMultipleRecipients method.