How to write attachment from attachment of an email?

Question

I am fetch the email with attachment if found attachment then forward that email to some user. I used following code to do so. When I am using below code it sends email with attachment but attachment has no content (blank attachment). can you suggest me where I am wrong?

public bool AddAttachment(System.IO.Stream sm, string fileName)
    {
        try
        {
            System.Net.Mail.Attachment atch = new System.Net.Mail.Attachment(sm, fileName);
            msg.Attachments.Add(atch);
            return true;
        }
        catch (Exception ex)
        {
            TraceService(ex.Message + Environment.NewLine + Environment.NewLine + ex.StackTrace);
        }
        return false;
    }

 ObjMail.MsgData = strBuilder.ToString();
            for (int i = 0; i < sMail.Attachments.Length; i++)
            {
                if (!string.IsNullOrEmpty(sMail.Attachments[i].Name))
                {
                    if (!sMail.Attachments[i].Name.Contains(".dat"))
                    {
                        System.IO.MemoryStream ms = new System.IO.MemoryStream();
                        System.IO.StreamWriter writer = new System.IO.StreamWriter(ms);
                        var sr = new StreamReader(ms);
                        writer.Write(sMail.Attachments[i]);

                        ObjMail.AddAttachment(ms, sMail.Attachments[i].Name);
                    }
                }   
            }
ObjMail.SendMail();

Answer 1

To attach use the following code I have used the example to attach a JPG Image

Attachment attach = new Attachment(id + ".jpg");
attach.Name = "WhateverName.jpg";
mail.Attachments.Add(attach);

Answer 2

Try this:

if (!string.IsNullOrEmpty(sMail.Attachments[i].Name))
                {
                    if (!sMail.Attachments[i].Name.Contains(".dat"))
                    {
                        System.IO.MemoryStream ms = new System.IO.MemoryStream();
                        sMail.Attachments[i].ContentStream.CopyTo(ms);

                        ObjMail.AddAttachment(ms, sMail.Attachments[i].Name);
                    }
                }

Or may be you can use simple:

if (!string.IsNullOrEmpty(sMail.Attachments[i].Name))
                    {
                        if (!sMail.Attachments[i].Name.Contains(".dat"))
                        { 
                           ObjMail.Add(sMail.Attachments[i]);
                        }
                    }
ObjMail.SendMail();