Sending Mails with attachment in C#

I need to send a mail including the exception details (Yellow Screen Of Death) as attachment.

I could get the YSOD as follows:

string YSODmarkup = lastErrorWrapper.GetHtmlErrorMessage();
if (!string.IsNullOrEmpty(YSODmarkup))
{
    Attachment YSOD = Attachment.CreateAttachmentFromString(YSODmarkup, "YSOD.htm");
    mm.Attachments.Add(YSOD);
}

mm is of type MailMessage, but the mail is not sent.

Here

System.Net.Mail.MailMessage MyMailMessage = new System.Net.Mail.MailMessage("from", "to", "Exception-Details", htmlEmail.ToString());

is used to bind the body of the mail.

After this only the attachment is added. While removing the attachment, mail is sent.

Can anyone help me out?

---

As per the comments from Mr. Albin开发者_运维问答 and Mr. Paul am updating the following

        string YSODmarkup = Ex_Details.GetHtmlErrorMessage();
        string p = System.IO.Directory.GetCurrentDirectory();
        p = p + "\\trial.txt";
        StreamWriter sw = new StreamWriter(p);
        sw.WriteLine(YSODmarkup);
        sw.Close();
        Attachment a = new Attachment(p);       

        if (!string.IsNullOrEmpty(YSODmarkup))
        {
             Attachment  YSOD = Attachment.CreateAttachmentFromString(YSODmarkup, "YSOD.html");
            System.Net.Mail.Attachment(server.mappath("C:\\Documents and Settings\\user\\Desktop\\xml.docx"));

             MyMailMessage.Attachments.Add(a);

        }  

Here i attached the contents to a text file and tried the same. So the mail was not sent. Is there any issue with sending mails which contains HTML tags in it. Because i was able to attach a normal text file.

---

namespace SendAttachmentMail
{
    class Program
    {
        static void Main(string[] args)
        {
            var myAddress = new MailAddress("jhered@yahoo.com","James Peckham");
            MailMessage message = new MailMessage(myAddress, myAddress);
            message.Body = "Hello";
            message.Attachments.Add(new Attachment(@"Test.txt"));
            var client = new YahooMailClient();
            client.Send(message);
        }
    }
    public class YahooMailClient : SmtpClient
    {
        public YahooMailClient()
            : base("smtp.mail.yahoo.com", 25)
        {
            Credentials = new YahooCredentials();
        }
    }
    public class YahooCredentials : ICredentialsByHost
    {
        public NetworkCredential GetCredential(string host, int port, string authenticationType)
        {
            return new NetworkCredential("jhered@yahoo.com", "mypwd");
        }
    }
}