发送HTML电子邮件与嵌入式图像和相同的图像在C＃中附件的纯文本 [英] Send html email with embedded image and plain text with same image as attachment in C#

问题描述

我想发送一封电子邮件，以纯文本和HTML版本。电子邮件需要一个形象去用它（而不是一个我可以承载其他地方），它应该在客户端的HTML视图它被嵌入，并附上纯文本视图。

I wish to send an email, with a plain text and html version. The email needs an image to go with it (not one I can host somewhere else), it should be embedded if the client views it in html, and attached for the plain text view.

这是可以做到的，将在所有常用的客户端工作？

Is this possible to do that would work in all common clients?

我来最接近的是创建图像以附件形式（而不是链接的资源），然后引用它与CID的HTML：filename.jpg。然而，这在Gmail中无法正常工作（不显示HTML中的图像）。

The closest I have come is creating the image as an attachment (rather than a linked resource) then referencing it in the html with cid:filename.jpg. However this doesn't work in gmail (it doesn't display the image in the html).

推荐答案

此代码片段作品在2010年的前景和Gmail。我暂时把纯文本部分去年在电子邮件中，这使得Gmail的使用测试纯文本电子邮件。

This code snippet works in outlook 2010 and gmail. I test the plain text email by temporarily putting the plain text part last in the email, which makes gmail use that.

这也证明了其他一些很酷的东西，电子邮件模板，和标记替换。

It also demonstrates some other cool stuff such as email templates and tag substitution.

public void SendEmailWithPicture(string email, byte[] image)
{
    string filename = "AttachmentName.jpg";

    LinkedResource linkedResource = new LinkedResource(new MemoryStream(image), "image/jpg");
    linkedResource.ContentId = filename;
    linkedResource.ContentType.Name = filename;

    this.Send(
        EmailTemplates.sendpicture,
        this.Subjects.SendPicture,
        new List() { email },
        this.ReplyTo,
        tagValues: new Dictionary() { { "ImageAttachmentName", "cid:" + filename } },
        htmlLinkedResources: new List() { linkedResource }
        );
}

private void Send(EmailTemplates template, string subject, List to, string replyTo,
    Dictionary tagValues = null, List attachments = null, List htmlLinkedResources = null)
{
    try
    {
        MailMessage mailMessage = new MailMessage();

        // Set up the email header.
        to.ForEach(t => mailMessage.To.Add(new MailAddress(t)));
        mailMessage.ReplyToList.Add(new MailAddress(replyTo));
        mailMessage.Subject = subject;

        string fullTemplatePath = Path.Combine(this.TemplatePath, EMAIL_TEMPLATE_PATH);

        // Load the email bodies
        var htmlBody = File.ReadAllText(Path.Combine(fullTemplatePath, Path.ChangeExtension(template.ToString(), "html")));
        var textBody = File.ReadAllText(Path.Combine(fullTemplatePath, Path.ChangeExtension(template.ToString(), "txt")));

        // Replace the tags in the emails
        if (tagValues != null)
        {
            foreach (var entry in tagValues)
            {
                string tag = "{{" + entry.Key + "}}";

                htmlBody = htmlBody.Replace(tag, entry.Value);
                textBody = textBody.Replace(tag, entry.Value);
            }
        }

        // Create plain text alternative view
        string baseTxtTemplate = File.ReadAllText(Path.Combine(fullTemplatePath, TXT_BASE_TEMPLATE));
        textBody = baseTxtTemplate.Replace(TAG_CONTENT, textBody);
        AlternateView textView = AlternateView.CreateAlternateViewFromString(textBody, new System.Net.Mime.ContentType("text/plain"));

        // Create html alternative view
        string baseHtmlTemplate = File.ReadAllText(Path.Combine(fullTemplatePath, HTML_BASE_TEMPLATE));
        htmlBody = baseHtmlTemplate.Replace(TAG_CONTENT, htmlBody);
        AlternateView htmlView = AlternateView.CreateAlternateViewFromString(htmlBody, new System.Net.Mime.ContentType("text/html"));
        // Add any html linked resources
        if (htmlLinkedResources != null)
        {
            htmlLinkedResources.ForEach(lr => htmlView.LinkedResources.Add(lr));
            htmlLinkedResources.ForEach(lr => textView.LinkedResources.Add(lr));
        }

        // Add the two views (gmail will always display plain text version if its added last)
        mailMessage.AlternateViews.Add(textView);
        mailMessage.AlternateViews.Add(htmlView);

        // Add any attachments
        if (attachments != null)
        {
            attachments.ForEach(a => mailMessage.Attachments.Add(a));
        }

        // Send the email.
        SmtpClient smtp = new SmtpClient();
        smtp.Send(mailMessage);
    }
    catch (Exception ex)
    {
        throw new Exception(String.Format("Error sending email (to:{0}, replyto:{1})", String.Join(",", to), replyTo), ex);
    }
}

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