C＃如何从远程网站发送带有附件的电子邮件

Question

(Had to repost this because I did something pretty dumb in the original...)

NOTE: I'm very new at programming.

I can email an attachment from my computer, but how do I send an attachment via the interwebs, for example: http://blah.com/image.jpg as opposed to @"C:\\Users\\me\\pictures\\picture.jpg"?

Thanks in advance.

Here's what I have:

class Program
    {
        public const string GMAIL_SERVER = "smtp.gmail.com";
        public const int PORT = 587;

        static void Main(string[] args)
        {
            Console.WriteLine("Mail To:");
            MailAddress to = new MailAddress(Console.ReadLine());

            Console.WriteLine("Mail From:");
            MailAddress from = new MailAddress(Console.ReadLine());

            MailMessage mail = new MailMessage(from, to);

            Console.WriteLine("Subject:");
            mail.Subject = Console.ReadLine();

            mail.Attachments.Add(new Attachment(@"C:\Users\me\pictures\picture.jpg"));
            //Not sure how to send from a remote website...

            Console.WriteLine("Your Message:");
            mail.Body = Console.ReadLine();

            SmtpClient smtp = new SmtpClient(GMAIL_SERVER, PORT);
            smtp.Host = "smtp.gmail.com";
            smtp.Port = 587;

            smtp.Credentials = new NetworkCredential(
                "myemail", "password");
            smtp.EnableSsl = true;
            Console.WriteLine("Sending email... Please wait...");

            smtp.Send(mail);
            Console.WriteLine("Finshed!\n");

        }
    }

Answer 1

You would need to download the file and add it as an attachment as you have already done.

Somthing like

string localFilename = @"c:\localpath\tofile.jpg";
using(WebClient client = new WebClient())
{
    client.DownloadFile("http://www.example.com/image.jpg", localFilename);
}

will download the file.

Answer 2

Download the Image first and then just use the local file, or use a Stream and directly use it in the Attachment's Constructor. See https://msdn.microsoft.com/library/system.net.mail.attachment(v=vs.110).aspx . For the first approach, just use a WebClient with .DownloadFile. For the second, try:

WebClient client = new WebClient();
client.OpenReadCompleted += (s, e) =>
     {
         // e.Result is your stream containing the image. 
     };
client.OpenReadAsync(new Uri(imageUrl));