Regarding Mail Send

System.Web.Mail; 

protected void btSend_Click(object sender, EventArgs e)
    {
        if (!(txtMymail.Text.Equals(string.Empty)) && !(txtRecivermail.Text.Equals(string.Empty)) && !(txtSubject.Text.Equals(string.Empty)) && !(txtBody.Text.Equals(string.Empty)))
        {
            //SmtpClient mailClient = new SmtpClient("smtp.gmail.com");
            string from = txtMymail.Text.ToString();
            string to = txtRecivermail.Text.ToString();
            string subject = txtSubject.Text.ToString();
            string body = txtBody.Text.ToString();
            System.Web.Mail.MailMessage mail12 = new System.Web.Mail.MailMessage();
            mail12.From =from;
            mail12.To = to;
            mail12.Subject = subject;
            mail12.Body = body;

            mail12.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpserver", "smtp.gmail.com");
            mail12.Fields.Add("http://schemas.microsoft.com/cdo/configuration/smtpserverport", 587);
            mail12.Fields.Add("http://schemas.microsoft.com/cdo/configuration/sendusing", 2);
            mail12.Fields.Add("http://schemas.microsoft.com/cdo/configuration/sendusername", "vinoar@gmail.com");
            mail12.Fields.Add("http://schemas.microsoft.com/cdo/configuration/sendpassword", "vinoth123");

            try
            {
                System.Web.Mail.SmtpMail.Send(mail12);
                //mailClient.Send(mail12);
            }
            catch (Exception exp)
            {
                lbErr.Visible = true;
                lbErr.ForeColor = Color.Red;
                lbErr.Text = "Error During Send mail" + exp.ToString();
            }
            lbErr.Visible = true;
            lbErr.ForeColor = Color.Blue;
            lbErr.Text = "Mail Send";
        }
        else
        {
            lbErr.Visible = true;
            lbErr.ForeColor = Color.Red;
            lbErr.Text = "Fill The Fields";
        }
    }