// Attach the message string to this e-mail message.
//var reader = new StreamReader(@"c:Temptelephone.txt");
string path = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop), "telephone.txt");


Attachment data = new Attachment(path, MediaTypeNames.Text.Plain);

// Send textMessage as part of the e-mail body.
message.Attachments.Add(data);
ContentDisposition disposition = data.ContentDisposition;
disposition.Inline = true;
message.Attachments[0].ContentId = "telephone.txt";

//Send the message.
// Include credentials if the server requires them.
SmtpClient client = new SmtpClient(server);
client.Credentials = CredentialCache.DefaultNetworkCredentials;

try
{
    client.Send(message);
}
catch (Exception ex)
{
    Console.WriteLine("Exception caught in CreateMessageInlineAttachment: {0}",
                        ex.ToString());
}
data.Dispose();