How to embed multiple images in email body using .NET
I'm writing a program that sends emails to users with multiple images (charts) embedded in the Email message body (HTML).
When I tried the sample located here..which worked well when I have to embed only one image http://www.systemnetmail.com/faq/4.4.aspx.
But, when i tried to embed multiple images using the below code, none of the images are being embedded , instead they are sent as attachments.
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;
}
Any clues as what I'm missing? I checked the .htm file which is also sent as attachment with the email, and html source looks as follows:
<html>><body><img s开发者_开发知识库rc=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>
So the Q is how to send multiple images in the html body , not as attachment.
The other way to embed images in E-mail when using System.Net.Mail is
Attach image from local drive to email and assign a contentID to it and later use this contentID in the image URL.
This can be done by:
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>";
First, you could try to use absolute URIs to embedded images. Here is example from RFC-2557:
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--
You just need to assign LinkedResource.ContentLink property instead of ContentId.
Second, you could embed images directly to your html with the "data" URL scheme.
<IMG
SRC="data:image/gif;base64,R0lGODdhMAAwAPAAAAAAAP///ywAAAAAMAAw
AAAC8IyPqcvt3wCcDkiLc7C0qwyGHhSWpjQu5yqmCYsapyuvUUlvONmOZtfzgFz
ByTB10QgxOR0TqBQejhRNzOfkVJ+5YiUqrXF5Y5lKh/DeuNcP5yLWGsEbtLiOSp
a/TPg7JpJHxyendzWTBfX0cxOnKPjgBzi4diinWGdkF8kjdfnycQZXZeYGejmJl
ZeGl9i2icVqaNVailT6F5iJ90m6mvuTS4OK05M0vDk0Q4XUtwvKOzrcd3iq9uis
F81M1OIcR7lEewwcLp7tuNNkM3uNna3F2JQFo97Vriy/Xl4/f1cf5VWzXyym7PH
hhx4dbgYKAAA7"
ALT="Larry">
BTW, your html markup is not well-formed. You may also be interested in “foreach” vs “ForEach”
So, I think figured out what the actual problem is Its in this line
// Alternate view for embedded images
AlternateView avText = AlternateView.CreateAlternateViewFromString(metric.Name, null, MediaTypeNames.Text.Html);
AlternateView avImages = AlternateView.CreateAlternateViewFromString(htmlBody, null, MediaTypeNames.Text.Html);
As you can see, both my views are specified as Text.Html, so the the 1st one is overriding the next one and so I only see text and images are sent as attachments
I made the following change and it worked as expected
AlternateView avText = AlternateView.CreateAlternateViewFromString(metric.Name, null, **MediaTypeNames.Text.Plain**);
AlternateView avImages = AlternateView.CreateAlternateViewFromString(htmlBody, null, MediaTypeNames.Text.Html);
My alternatie:
First of all, a little extension:
public static class RegexExtensions
{
public static string GetPattern(this IEnumerable<string> valuesToSearch)
{
return string.Format("({0})", string.Join("|", valuesToSearch));
}
}
then get image names from folder:
private string[] GetFullNamesOfImages()
{
string images = Path.Combine(_directoryName, "Images");
if (!Directory.Exists(images))
return new string[0];
return Directory.GetFiles(images);
}
then replacing image names by cid:
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);
}
where body - is HTML body, and for example, <img src="Images/logo_shadow.png" alt="" style="width: 100%;" /> will be replaced by <img src="cid:logo_shadow.png" alt="" style="width: 100%;" />
then last action: adding images itselfs to mail:
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;
}
if you have the images online, meaning sending from a hosted site, i suggest you just reference those images simply by putting their url in the src.
<!-- using artplastika examples -->
<IMG SRC="http://www.ietf.cnri.reston.va.us/images/ietflogo.gif" ALT="IETF logo" />
most of the newsletters use this method, and i believe it's lighter and can consume less resources than embedding itself.
hope this helps
AlternateView avHtml = AlternateView.CreateAlternateViewFromString(body, null, MediaTypeNames.Text.Html);
LinkedResource inline = new LinkedResource(System.Web.HttpContext.Current.Server.MapPath("~/Images/e1.jpg"), MediaTypeNames.Image.Jpeg);
inline.ContentId = "1";
inline.TransferEncoding = System.Net.Mime.TransferEncoding.Base64;
avHtml.LinkedResources.Add(inline);
LinkedResource inline1 = new LinkedResource(System.Web.HttpContext.Current.Server.MapPath("~/CImages/2.jpg"), MediaTypeNames.Image.Jpeg);
inline1.ContentId = "2";
inline1.TransferEncoding = System.Net.Mime.TransferEncoding.Base64;
avHtml.LinkedResources.Add(inline1);
LinkedResource inline2 = new LinkedResource(System.Web.HttpContext.Current.Server.MapPath("~/Images/3.jpg"), MediaTypeNames.Image.Jpeg);
inline2.ContentId = "3";
inline2.TransferEncoding = System.Net.Mime.TransferEncoding.Base64;
avHtml.LinkedResources.Add(inline2);
LinkedResource inline3 = new LinkedResource(System.Web.HttpContext.Current.Server.MapPath("~/Content/Images/4.jpg"), MediaTypeNames.Image.Jpeg);
inline3.ContentId = "4";
inline3.TransferEncoding = System.Net.Mime.TransferEncoding.Base64;
avHtml.LinkedResources.Add(inline3);
MailMessage mail = new MailMessage();
mail.AlternateViews.Add(avHtml);
HTML:
<img src="cid:1" alt="" />
<img src="cid:2" alt="" />
<img src="cid:3" alt="" /`
<img src="cid:4" alt="" />
Try the following:
private static ICollection<LinkedResource> GetLinkedResources()
{
var linkedResources = new List<LinkedResource>();
linkedResources.Add(new LinkedResource(@"imagepath")
{
ContentId = "HeaderId",
TransferEncoding = TransferEncoding.Base64
});
linkedResources.Add(new LinkedResource(@"imagepath")
{
ContentId = "MapId",
TransferEncoding = TransferEncoding.Base64
});
return linkedResources;
}
Then you can call the method as follows:
mailMessage.AlternateViews.Add(GetEmbeddedImage(body));
加载中,请稍侯......
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