C# windows forms send email using smtp

Question

I want to use windows application to send email to a account (both gmail). I tried using following code :

private void button2_Click(object sender, EventArgs e)
{
    try 
    {
        using (SmtpClient client = new SmtpClient("smtp.gmail.com"))
        {
            MailMessage message = new MailMessage();
            message.From = new MailAddress(textBox1.Text);
            message.To.Add(textBox3.Text);
            message.Body = textBox6.Text;
            message.Subject = textBox5.Text;
            client.UseDefaultCredentials = false;
            client.Port = 587;
            client.EnableSsl = true;

            if (textBox4.Text != null)
            {
                message.Attachments.Add(new Attachment(textBox4.Text));
            }
            client.Credentials = new System.Net.NetworkCredential(textBox1.Text, textBox2.Text);
            client.Send(message);
            message = null;
            MessageBox.Show("sent");
        }
    }
    catch (SmtpFailedRecipientsException sfrEx)
    {
        // TODO: Handle exception
        // When email could not be delivered to all receipients.
        throw sfrEx;
    }
    catch (SmtpException sEx)
    {
        // TODO: Handle exception
        // When SMTP Client cannot complete Send operation.
        throw sEx;
    }
    catch (Exception ex)
    {
        // TODO: Handle exception
        // Any exception that may occur during the send process.
        throw ex;
    }  
}

private void button1_Click_1(object sender, EventArgs e)
{
    if (openFileDialog1.ShowDialog()==DialogResult.OK)
    {
        textBox4.Text= openFileDialog1.FileName.ToString();
    }
}

But when I click button2(send) it does nothing, not even exception I don't know what is the problem.neither it throws error nor sends the mail and my firewall is off.

any help would be really appreciated, thanks