使用 c# windows 应用程序在电子邮件正文中添加多个图像（内联）

Question

我搜索了几次并找到了解决方案，但都只支持一个图像。最后我使用了这个代码。 但问题是，如果 html 包含多张图片，则正文中只会显示一张图片，其他图片将作为附件出现。

string inputHtmlContent = htmlbody;
string outputHtmlContent = string.Empty;
var myResources = new List<LinkedResource>();

if ((!string.IsNullOrEmpty(inputHtmlContent)))
{
  var doc = new HtmlAgilityPack.HtmlDocument();
  doc.LoadHtml(inputHtmlContent);
  HtmlNodeCollection nodes = doc.DocumentNode.SelectNodes("//img");
  if (nodes !=null)
  {
    foreach (HtmlNode node in nodes)
    {
      if (node.Attributes.Contains("src"))
      {
        string data = node.Attributes["src"].Value;
        string imgPath = Application.StartupPath+"\\"+data;
        var imgLogo = new LinkedResource(imgPath);
        imgLogo.ContentId = Guid.NewGuid().ToString();
        imgLogo.ContentType = new ContentType("image/jpeg");
        myResources.Add(imgLogo);
        node.Attributes["src"].Value = string.Format("cid:{0}", imgLogo.ContentId);
        outputHtmlContent = doc.DocumentNode.OuterHtml;
      }
    }
  }
  else
  {
    outputHtmlContent = inputHtmlContent;
  }
  AlternateView av2 = AlternateView.CreateAlternateViewFromString(outputHtmlContent,
                            null, MediaTypeNames.Text.Html);
  foreach (LinkedResource linkedResource in myResources)
  {
    av2.LinkedResources.Add(linkedResource);
  }

  msg.AlternateViews.Add(av2);

请帮我解决这个问题，如何在电子邮件正文中显示所有图像？...

Answer 1

试试这个代码。这将为 excel 、 csv 、 pdf 以及内联附件生成附件，即在电子邮件正文中生成 png 格式的图像。 对于 png 格式，多个图像将通过 GetEmbeddedImage 方法逐个嵌入内联。您可以根据自己的要求对其进行自定义。

SmtpClient smtpServer = new SmtpClient(smtpServerName);
smtpServer.Port = 25;
smtpServer.Credentials = new System.Net.NetworkCredential(userName, password);
//smtpServer.EnableSsl = true;
MailMessage smtpEmail = new MailMessage();
string messageBodyImage = @"<img width=1200 id=""MyContent"" src=""cid:{0}"">";
 toAddressList = toAddress.Split(';');
foreach (string toEmail in toAddressList)
    smtpEmail.To.Add(toEmail);

smtpEmail.From = new MailAddress(fromAddress);
smtpEmail.Body = messageBody;
smtpEmail.Subject = subject;
foreach (string format in fileExtension)
 {    
    switch (format)
     {       
    case "PNG": 
    smtpEmail.IsBodyHtml = true;
    smtpEmail.AlternateViews.Add(GetEmbeddedImage(reportByteStream, messageBodyImage, format)); 
    break;
    case "CSV":      
    smtpEmail.Attachments.Add(new System.Net.Mail.Attachment(new MemoryStream(myStream[format][0]), "MyReport." + format, "text/csv"));  
    break;
    case "XLS": 
    smtpEmail.Attachments.Add(new System.Net.Mail.Attachment(new MemoryStream(myStream[format][0]), "MyReport." + format, "application/vnd.ms-excel"));
    break;
    default: // For PDF
    smtpEmail.Attachments.Add(new System.Net.Mail.Attachment(new MemoryStream(myStream[format][0]), "MyReport." + format, MediaTypeNames.Application.Pdf));
    break;
    }
}

内嵌多张图片的方法。

    private AlternateView GetEmbeddedImage(Dictionary<string, Byte[][]> streamAttachment, string msgTemplate, string fileFormat)
    {
        LinkedResource imageFile = null;
        AlternateView alternateView = null;
        string msgBody = string.Empty;
        try
        {
        List<LinkedResource> imageFiles = new List<LinkedResource>();
        for (int page = 0; page < streamAttachment[fileFormat].Length; page++)
        {   
                imageFile = new LinkedResource(new MemoryStream(streamAttachment[fileFormat][page]));
                imageFile.ContentId = Guid.NewGuid().ToString();
                msgBody = msgBody + "<BR/>" + string.Format(msgTemplate, imageFile.ContentId);
                imageFiles.Add(imageFile); 
        }

        alternateView = AlternateView.CreateAlternateViewFromString(msgBody, null, MediaTypeNames.Text.Html);
        imageFiles.ForEach(img => alternateView.LinkedResources.Add(img));
        }
        catch (Exception Ex)
        {

        }
        return alternateView;
    } 

Answer 2

您可以将图片附加到邮件中，然后将img 标签和附件的ContentId 用作src 这种方式：

private void denMailButton_Click(object sender, EventArgs e)
{
    string subject = "Subject";
    string body = @"Image 1: <img src=""$CONTENTID1$""/> <br/> Image 2: <img src=""$CONTENTID2$""/> <br/> Some Other Content";

    MailMessage mail = new MailMessage();
    mail.From = new MailAddress("from@example.com");
    mail.To.Add(new MailAddress("to@example.com"));
    mail.Subject = subject;
    mail.Body = body;
    mail.Priority = MailPriority.Normal;

    string contentID1 = Guid.NewGuid().ToString().Replace("-", "");
    string contentID2 = Guid.NewGuid().ToString().Replace("-", "");

    body = body.Replace("$CONTENTID1$", "cid:" + contentID1);
    body = body.Replace("$CONTENTID2$", "cid:" + contentID2);

    AlternateView htmlView = AlternateView.CreateAlternateViewFromString(body, null, "text/html");

    //path of image or stream
    LinkedResource imagelink1 = new LinkedResource(@"D:\1.png", "image/png");
    imagelink1.ContentId = contentID1;
    imagelink1.TransferEncoding = System.Net.Mime.TransferEncoding.Base64;
    htmlView.LinkedResources.Add(imagelink1);

    LinkedResource imagelink2 = new LinkedResource(@"D:\2.png", "image/png");
    imagelink2.ContentId = contentID2;
    imagelink2.TransferEncoding = System.Net.Mime.TransferEncoding.Base64;
    htmlView.LinkedResources.Add(imagelink2);

    mail.AlternateViews.Add(htmlView);

    SmtpClient client = new SmtpClient();
    client.Host = "mail.example.com";
    client.Credentials = new NetworkCredential("from@example.com", "password");
    client.Send(mail);
}

这是截图：