将图像嵌入到System.Web.Mail.MailMessage中的电子邮件中 [英] Embed image to email message in System.Web.Mail.MailMessage
问题描述
我想使用System.Web.Mail.MailMessage和System.Web.Mail.SmtpMail类一起发送电子邮件。
我知道这是一个不推荐的类，但使用System.Net.Mail不是我的选择。
I want to send email using System.Web.Mail.MailMessage along with System.Web.Mail.SmtpMail class. I know that this is a deprecated class but using System.Net.Mail is not an option for me.
到目前为止，我可以发送html格式邮件，但我无法在发送时将图像嵌入到我的电子邮件。
So far I am able to send html formatted mail but I am not able to embed image to my email while sending.
这是我迄今为止所尝试的;
This is what I've tried so far;
private static void SendMailMethod(string mailServer, int mailServerPort, string userName, string password)
{
const string SMTP_SERVER = "http://schemas.microsoft.com/cdo/configuration/smtpserver";
const string SMTP_SERVER_PORT =
"http://schemas.microsoft.com/cdo/configuration/smtpserverport";
const string SEND_USING = "http://schemas.microsoft.com/cdo/configuration/sendusing";
const string SMTP_USE_SSL = "http://schemas.microsoft.com/cdo/configuration/smtpusessl";
const string SMTP_AUTHENTICATE =
"http://schemas.microsoft.com/cdo/configuration/smtpauthenticate";
const string SEND_USERNAME =
"http://schemas.microsoft.com/cdo/configuration/sendusername";
const string SEND_PASSWORD =
"http://schemas.microsoft.com/cdo/configuration/sendpassword";
var mailMessage = new System.Web.Mail.MailMessage();
mailMessage.Fields[SMTP_SERVER] = mailServer;
mailMessage.Fields[SMTP_SERVER_PORT] = mailServerPort;
mailMessage.Fields[SEND_USING] = 2;
mailMessage.Fields[SMTP_USE_SSL] = false;
mailMessage.Fields[SMTP_AUTHENTICATE] = 0;
mailMessage.Fields[SEND_USERNAME] = userName;
mailMessage.Fields[SEND_PASSWORD] = password;
mailMessage.From = "abc@xyz.com";
mailMessage.To = "abc@xyz.com";
mailMessage.Subject = "Test mail:";
mailMessage.BodyFormat = MailFormat.Html;
var mailAttachment = new MailAttachment("E:\\imageToEmbed.jpg");
mailMessage.Attachments.Add(mailAttachment);
mailMessage.Attachments.Add(new MailAttachment("E:\\TestAttachmentFile.txt"));
var htmlBody =
"<!DOCTYPE html PUBLIC \" -//W3C//DTD XHTML 1.0 Transitional//EN\" \"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd\">" +
"<html xmlns = \"http://www.w3.org/1999/xhtml\" >" +
" <head >" +
"<meta http - equiv = \"content-type\" content = \"text/html; charset=UTF-8\" />" +
"</head >" +
"<body style = \"font-family: Segoe UI; text-align:left;\" >" +
"Following is an embedded image:" +
"<br />" +
"<img alt = \"\" src = \"imageToEmbed.jpg\" />" +
"</body >" +
"</html >";
mailMessage.Body = htmlBody;
try
{
SmtpMail.Send(mailMessage);
Console.WriteLine("Mail sent");
}
catch (Exception ex)
{
Console.WriteLine("Error:" + ex.ToString());
throw ex;
}
}
此代码发送电子邮件，而不是显示图像邮件显示小方块与十字架。
如何将此imageToEmbed.jpg嵌入到我的电子邮件中。
This code sends email but instead of showing image, the mail shows small square with a cross in it. How can I embed this "imageToEmbed.jpg" to my email.
推荐答案
您无法使用类 System.Web.Mail 因为该实现将访问许多基本的协作数据对象组件。
You can't achieve that with the classes System.Web.Mail because that implementation abstracts the access to a lot of features of the underlying Collaboration Data Objects component.
而不是使用由 System.Web.Mail.Message提供的包装器你最好直接使用CDO COM对象。在参考对话框的COM选项卡中添加对 Microsoft CDO for Windows 2000 Library 的引用。
之后可以使用以下代码创建和发送带嵌入图像的html电子邮件：
After that you can use the following code to create and send an html email with embedded images:
var cdo = new CDO.Message();
// configuration
var cfg = cdo.Configuration;
cfg.Fields[SMTP_SERVER].Value = "smtp.server.com";
cfg.Fields[SMTP_SERVER_PORT].Value = 22;
cfg.Fields[SEND_USING].Value = 2;
cfg.Fields[SMTP_USE_SSL].Value = true;
cfg.Fields[SMTP_AUTHENTICATE].Value = 1;
cfg.Fields[SEND_USERNAME].Value = "user@example.com";
cfg.Fields[SEND_PASSWORD].Value = "password";
cfg.Fields.Update();
cdo.To = "awesome@example.com";
cdo.Sender = "me@example.com";
// attachment
var cdoatt = cdo.AddAttachment("file:///E:/imageToEmbed.jpg");
//this is why System.Web.Mail can't embed images
cdoatt.Fields["urn:schemas:mailheader:content-id"].Value = Guid.NewGuid().ToString("N");
cdoatt.Fields.Update();
// get a reference to out content-id field
var cid = cdoatt.Fields["urn:schemas:mailheader:content-id"];
// notice the special layout of SRC on the image tag,
//it will be somethong like CID:123456789abcdef
cdo.HTMLBody = @"<HTML><BODY><B>CDO</B><BR /> <IMG SRC=""cid:" + cid.Value + @"""/></BODY></HTML>";
cdo.Send();
请注意如何在附件上设置Content-ID标题。这是必需的，因此您可以在图像的SRC属性中使用Content-ID。
Notice how you can set the Content-ID header here on the Attachment. That is needed so you can use the Content-ID in the SRC attribute of your image.
典型的邮件消息将显示
MIME-Version: 1.0
Content-Type: multipart/mixed;
boundary="----=_NextPart_000_0001_01D1AF72.C8AE8C70"
Content-Transfer-Encoding: 7bit
X-Mailer: Microsoft CDO for Windows 2000
Content-Class: urn:content-classes:message
Importance: normal
Priority: normal
X-MimeOLE: Produced By Microsoft MimeOLE V10.0.10011.16384
This is a multi-part message in MIME format.
------=_NextPart_000_0001_01D1AF72.C8AE8C70
Content-Type: multipart/alternative;
boundary="----=_NextPart_001_0002_01D1AF72.C8AE8C70"
------=_NextPart_001_0002_01D1AF72.C8AE8C70
Content-Type: text/plain;
charset="iso-8859-1"
Content-Transfer-Encoding: 7bit
plain cdo
------=_NextPart_001_0002_01D1AF72.C8AE8C70
Content-Type: text/html;
charset="iso-8859-1"
Content-Transfer-Encoding: 7bit
<HTML><BODY><B>plain cdo</B> <IMG SRC="cid:42"/></BODY></HTML>
------=_NextPart_001_0002_01D1AF72.C8AE8C70--
------=_NextPart_000_0001_01D1AF72.C8AE8C70
Content-Type: image/png;
name="file.png"
Content-Transfer-Encoding: base64
Content-ID: <42>
Content-Disposition: attachment;
filename="file.png"
iVBORw0KGgoAAAANSUhEUgAAADQAAABLCAMA
通知Content-ID（这里是42）。
Notice the Content-ID (here 42).
使用简单的 System.Web.Mail 将您的原始邮件将如下所示：
When using the plain System.Web.Mail classes your raw email will look like this:
MIME-Version: 1.0
Content-Type: multipart/mixed;
boundary="----=_NextPart_000_0000_01D1AF70.59FC25F0"
X-Mailer: Microsoft CDO for Windows 2000
Content-Class: urn:content-classes:message
Importance: normal
Priority: normal
X-MimeOLE: Produced By Microsoft MimeOLE V10.0.10011.16384
This is a multi-part message in MIME format.
------=_NextPart_000_0000_01D1AF70.59FC25F0
Content-Type: multipart/alternative;
boundary="----=_NextPart_001_0001_01D1AF70.59FC25F0"
------=_NextPart_001_0001_01D1AF70.59FC25F0
Content-Type: text/plain;
charset="iso-8859-1"
Content-Transfer-Encoding: 7bit
Following is an embedded image:
_____
test afterit
------=_NextPart_001_0001_01D1AF70.59FC25F0
Content-Type: text/html;
charset="iso-8859-1"
Content-Transfer-Encoding: 7bit
<!DOCTYPE html PUBLIC " -//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns = "http://www.w3.org/1999/xhtml" > <head ><meta http - equiv = "content-type" content = "text/html; charset=UTF-8" /></head ><body style = "font-family: Segoe UI; text-align:left;" ><i>Following is an embedded image:</i><br /><img alt = "" src ="<file:///file.png>"/><hr><b>test afterit</b></body ></html >
------=_NextPart_001_0001_01D1AF70.59FC25F0--
------=_NextPart_000_0000_01D1AF70.59FC25F0
Content-Type: image/png;
name="file.png"
Content-Transfer-Encoding: base64
Content-Disposition: attachment;
filename="file.png"
iVBORw0KGgoAAAANSUhEUgAAADQAAABLCAMAAAAI0l
As您可以看到，没有添加Content-ID标头，并且没有.Net实现的代码路径来添加该标题。
As you can see, there is no Content-ID header added and there is no code-path from the .Net implementation to add that header.
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