use*_*612 13 c# image system.net.mail
我正在编写一个程序,向用户发送电子邮件,其中包含嵌入电子邮件正文(HTML)中的多个图像(图表).
当我尝试这里的样本时......当我只需要嵌入一个图像http://www.systemnetmail.com/faq/4.4.aspx时效果很好 .
但是,当我尝试使用以下代码嵌入多个图像时,没有嵌入任何图像,而是将它们作为附件发送.
public MailMessage MailMessage(Metric metric, DateTime date)
{
MailMessage msg = new MailMessage();
msg.From = new MailAddress("test@gmail.com", "User1");
msg.To.Add(new MailAddress("test@gmail.com"));
msg.Subject = "Trend for metric: " + metric.Name;
msg.IsBodyHtml = true;
// Generate the charts for the given metric
var charts = this.GenerateCharts(metric, date);
int i = 0;
string htmlBody = "<html><body>";
List<LinkedResource> resources = new List<LinkedResource>();
foreach (var chart in charts)
{
string imageTag = string.Format("<img src=cid:chart{0} /><br>", i);
htmlBody += imageTag;
LinkedResource graph = new LinkedResource(chart.Value, "image/jpeg");
graph.ContentId = "chart" + i;
resources.Add(graph);
i++;
}
htmlBody += "</body></html>";
// Alternate view for embedded images
AlternateView avText = AlternateView.CreateAlternateViewFromString(metric.Name, null, MediaTypeNames.Text.Html);
AlternateView avImages = AlternateView.CreateAlternateViewFromString(htmlBody, null, MediaTypeNames.Text.Html);
// Add all the images as linked resources
resources.ForEach(x => avImages.LinkedResources.Add(x));
// Add the views for image
msg.AlternateViews.Add(avText);
msg.AlternateViews.Add(avImages);
return msg;
}
我缺少的任何线索？我检查了.htm文件,它也作为电子邮件附件发送,html源代码如下:
<html>><body><img src=cid:chart0 /><br><img src=cid:chart1 /><br><img src=cid:chart2/><br><img src=cid:chart3 /><br><img src=cid:chart4 /><br></body></html>
所以Q是如何在html体内发送多个图像,而不是附件.
小智 20
使用时将图像嵌入电子邮件的另一种方法System.Net.Mail是
将图像从本地驱动器附加到电子邮件并分配contentID给它,然后contentID在图像URL中使用它.
这可以通过以下方式完成:
var contentID = "Image";
var inlineLogo = new Attachment(@"C:\Desktop\Image.jpg");
inlineLogo.ContentId = contentID;
inlineLogo.ContentDisposition.Inline = true;
inlineLogo.ContentDisposition.DispositionType = DispositionTypeNames.Inline;
msg.IsBodyHtml = true;
msg.Attachments.Add(inlineLogo);
msg.Body = "<htm><body> <img src=\"cid:" + contentID + "\"> </body></html>";
所以,我想在这一行中找出实际问题是什么
// Alternate view for embedded images
AlternateView avText = AlternateView.CreateAlternateViewFromString(metric.Name, null, MediaTypeNames.Text.Html);
AlternateView avImages = AlternateView.CreateAlternateViewFromString(htmlBody, null, MediaTypeNames.Text.Html);
正如您所看到的,我的两个视图都指定为Text.Html,因此第一个视图将覆盖下一个视图,因此我只看到文本和图像作为附件发送
我做了以下更改,它按预期工作
AlternateView avText = AlternateView.CreateAlternateViewFromString(metric.Name, null, **MediaTypeNames.Text.Plain**);
AlternateView avImages = AlternateView.CreateAlternateViewFromString(htmlBody, null, MediaTypeNames.Text.Html);
首先,您可以尝试使用绝对URI来嵌入图像.以下是RFC-2557的示例:
From: foo1@bar.net
To: foo2@bar.net
Subject: A simple example
Mime-Version: 1.0
Content-Type: multipart/related; boundary="boundary-example";
type="text/html"; start="<foo3@foo1@bar.net>"
--boundary-example
Content-Type: text/html;charset="US-ASCII"
Content-ID: <foo3@foo1@bar.net>
... text of the HTML document, which might contain a URI
referencing a resource in another body part, for example
through a statement such as:
<IMG SRC="http://www.ietf.cnri.reston.va.us/images/ietflogo.gif" ALT="IETF logo">
--boundary-example
Content-Location:
http://www.ietf.cnri.reston.va.us/images/ietflogo.gif
Content-Type: IMAGE/GIF
Content-Transfer-Encoding: BASE64
R0lGODlhGAGgAPEAAP/////ZRaCgoAAAACH+PUNvcHlyaWdodCAoQykgMTk5
NSBJRVRGLiBVbmF1dGhvcml6ZWQgZHVwbGljYXRpb24gcHJvaGliaXRlZC4A
etc...
--boundary-example--
您只需要分配LinkedResource.ContentLink属性而不是ContentId.
其次,您可以使用"数据"URL方案将图像直接嵌入到html中.
<IMG
SRC="data:image/gif;base64,R0lGODdhMAAwAPAAAAAAAP///ywAAAAAMAAw
AAAC8IyPqcvt3wCcDkiLc7C0qwyGHhSWpjQu5yqmCYsapyuvUUlvONmOZtfzgFz
ByTB10QgxOR0TqBQejhRNzOfkVJ+5YiUqrXF5Y5lKh/DeuNcP5yLWGsEbtLiOSp
a/TPg7JpJHxyendzWTBfX0cxOnKPjgBzi4diinWGdkF8kjdfnycQZXZeYGejmJl
ZeGl9i2icVqaNVailT6F5iJ90m6mvuTS4OK05M0vDk0Q4XUtwvKOzrcd3iq9uis
F81M1OIcR7lEewwcLp7tuNNkM3uNna3F2JQFo97Vriy/Xl4/f1cf5VWzXyym7PH
hhx4dbgYKAAA7"
ALT="Larry">
顺便说一下,你的html标记格式不正确.你可能也对"foreach"vs"ForEach"感兴趣
我的替代者：
首先，稍微扩展一下：
public static class RegexExtensions
{
public static string GetPattern(this IEnumerable<string> valuesToSearch)
{
return string.Format("({0})", string.Join("|", valuesToSearch));
}
}
然后从文件夹中获取图像名称：
private string[] GetFullNamesOfImages()
{
string images = Path.Combine(_directoryName, "Images");
if (!Directory.Exists(images))
return new string[0];
return Directory.GetFiles(images);
}
然后用 cid 替换图像名称：
private string InsertImages(string body)
{
var images = GetFullNamesOfImages().Select(Path.GetFileName).ToArray();
return Regex.Replace(body, "(Images/)?" + images.GetPattern(), "cid:$2", RegexOptions.IgnoreCase | RegexOptions.Compiled);
}
其中 body - 是 HTML 正文，例如，<img src="Images/logo_shadow.png" alt="" style="width: 100%;" />将替换为<img src="cid:logo_shadow.png" alt="" style="width: 100%;" />
然后最后一个操作：将图像本身添加到邮件中：
private MailMessage CreateMail(SmtpClient smtp, string toAddress, string body)
{
var images = GetFullNamesOfImages();
string decodedBody = WebUtility.HtmlDecode(body);
var text = AlternateView.CreateAlternateViewFromString(decodedBody, null, MediaTypeNames.Text.Plain);
var html = AlternateView.CreateAlternateViewFromString(body, null, MediaTypeNames.Text.Html);
foreach (var image in images)
{
html.LinkedResources.Add(new LinkedResource(image, new ContentType("image/png"))
{
ContentId = Path.GetFileName(image)
});
}
var credentials = (NetworkCredential) smtp.Credentials;
var message = new MailMessage(new MailAddress(credentials.UserName), new MailAddress(toAddress))
{
Subject = "Some subj",
Body = decodedBody
};
message.AlternateViews.Add(text);
message.AlternateViews.Add(html);
return message;
}