sendgrid multiple recipients c#

Question

I'm using this code to send email from a web application. No problem with just one recipient. I've researched to use the same technic coming from https://sendgrid.com/docs/Integrate/Code_Examples/v3_Mail/csharp.html to send email to multiple recipients. I tried whith a comma delimited string as destinatario (see args in the code) i.e. [email protected], [email protected], [email protected] but SendGrid takes the first one recipient only. I also tried using an array but the result is simmilar, SG takes the last recipient only. What is the correct way to pass the list of recipients?

public class email
{
    public void enviar(string destinatario, string asunto, string contenido)
    {
        Execute(destinatario, asunto, contenido).Wait();
    }

    static async Task Execute(string destinatario, string asunto, string contenido)
    {
        string apiKey = "SG...............";
        dynamic sg = new SendGridAPIClient(apiKey);

        Email from = new Email("[email protected]");
        string subject = asunto;
        Email to = new Email(destinatario);
        Content content = new Content("text/plain", contenido);           

        Mail mail = new Mail(from, subject, to, content);
        dynamic response = await sg.client.mail.send.post(requestBody: mail.Get());
    }


}

Answer 1

You need to add the Personalizations list for that. Following code works for me.

var apiKey = Environment.GetEnvironmentVariable("SENDGRID_API_KEY");
var client = new SendGridClient(apiKey);
var msg = new SendGridMessage()
{
    From = new EmailAddress("[email protected]", "Sender Name"),
    Subject = "Subject",
    PlainTextContent = "Text for body",
    HtmlContent = "<strong>Hello World!",
    Personalizations = new List<Personalization>
    {
         new Personalization
         {
              Tos = new List<EmailAddress> 
              {
                   new EmailAddress("[email protected]", "abc"),
                   new EmailAddress("[email protected]", "efg")
              }
         }
     }
};

var response = await client.SendEmailAsync(msg);

For more details check following Mail Send