Hello I would like to ask how can I use this code inside WebMethod, since Im going to send an email using AJAX Jquery. Thanks!

 C#

using (MailMessage mm = new MailMessage(txtEmail.Text, txtTo.Text))
    {
        mm.Subject = txtSubject.Text;
        mm.Body = txtBody.Text;
        if (fuAttachment.HasFile)
        {
            string FileName = Path.GetFileName(fuAttachment.PostedFile.FileName);
            mm.Attachments.Add(new Attachment(fuAttachment.PostedFile.InputStream, FileName));
        }
        mm.IsBodyHtml = false;
        SmtpClient smtp = new SmtpClient();
        smtp.Host = "smtp.gmail.com";
        smtp.EnableSsl = true;
        NetworkCredential NetworkCred = new NetworkCredential(txtEmail.Text, txtPassword.Text);
        smtp.UseDefaultCredentials = true;
        smtp.Credentials = NetworkCred;
        smtp.Port = 587;
        smtp.Send(mm);
        ClientScript.RegisterStartupScript(GetType(), "alert", "alert('Email sent.');", true);
    }

VB

Using mm As New MailMessage(txtEmail.Text, txtTo.Text)
        mm.Subject = txtSubject.Text
        mm.Body = txtBody.Text
        If fuAttachment.HasFile Then
            Dim FileName As String = Path.GetFileName(fuAttachment.PostedFile.FileName)
            mm.Attachments.Add(New Attachment(fuAttachment.PostedFile.InputStream, FileName))
        End If
        mm.IsBodyHtml = False
        Dim smtp As New SmtpClient()
        smtp.Host = "smtp.gmail.com"
        smtp.EnableSsl = True
        Dim NetworkCred As New NetworkCredential(txtEmail.Text, txtPassword.Text)
        smtp.UseDefaultCredentials = True
        smtp.Credentials = NetworkCred
        smtp.Port = 587
        smtp.Send(mm)
        ClientScript.RegisterStartupScript(Me.GetType, "alert", "alert('Email sent.');", True)
    End Using

Link

Send email with attachment in ASP.Net using C# VB.Net