¿Por qué aparece el mensaje "No se puede asignar la propiedad" al enviar un correo electrónico SMTP?

No puedo entender por qué este código no funciona. Recibo un error que dice que la propiedad no se puede asignar.

MailMessage mail = new MailMessage();
SmtpClient client = new SmtpClient();
client.Port = 25;
client.DeliveryMethod = SmtpDeliveryMethod.Network;
client.UseDefaultCredentials = false;
client.Host = "smtp.gmail.com";
mail.To = "[email protected]"; // <-- this one
mail.From = "[email protected]";
mail.Subject = "this is a test email.";
mail.Body = "this is my test email body";
client.Send(mail);

Feb 09 '12 03:02 Sam Stephenson

Este :

mail.To = "[email protected]";

Debiera ser:

mail.To.Add(new MailAddress("[email protected]"));

Feb 08 '2012 20:02 Mithrandir

Finalmente me puse a trabajar :)

using System.Net.Mail;
using System.Text;

...

// Command line argument must the the SMTP host.
SmtpClient client = new SmtpClient();
client.Port = 587;
client.Host = "smtp.gmail.com";
client.EnableSsl = true;
client.Timeout = 10000;
client.DeliveryMethod = SmtpDeliveryMethod.Network;
client.UseDefaultCredentials = false;
client.Credentials = new System.Net.NetworkCredential("[email protected]","password");

MailMessage mm = new MailMessage("[email protected]", "[email protected]", "test", "test");
mm.BodyEncoding = UTF8Encoding.UTF8;
mm.DeliveryNotificationOptions = DeliveryNotificationOptions.OnFailure;

client.Send(mm);

perdón por la mala ortografía antes

Feb 26 '2012 19:02 Sam Stephenson

public static void SendMail(MailMessage Message)
{
    SmtpClient client = new SmtpClient();
    client.Host = "smtp.googlemail.com";
    client.Port = 587;
    client.UseDefaultCredentials = false;
    client.DeliveryMethod = SmtpDeliveryMethod.Network;
    client.EnableSsl = true;
    client.Credentials = new NetworkCredential("[email protected]", "password");
    client.Send(Message); 
}

Jul 28 '2012 11:07 Mnyikka

Así es como funciona para mí. Esperamos que te sea útil

MailMessage objeto_mail = new MailMessage();
SmtpClient client = new SmtpClient();
client.Port = 25;
client.Host = "smtp.internal.mycompany.com";
client.Timeout = 10000;
client.DeliveryMethod = SmtpDeliveryMethod.Network;
client.UseDefaultCredentials = false;
client.Credentials = new System.Net.NetworkCredential("user", "Password");
objeto_mail.From = new MailAddress("[email protected]");
objeto_mail.To.Add(new MailAddress("[email protected]"));
objeto_mail.Subject = "Password Recover";
objeto_mail.Body = "Message";
client.Send(objeto_mail);

Apr 29 '2013 17:04 user2332898