Inline-Bild per E-Mail senden

105

Probleme beim Senden eines Bildes per E-Mail als eingebettetes Bild im Körper. Die Bilddatei wird als Anhang angezeigt, was in Ordnung ist, aber der Inline-Bildteil wird nur als rotes x angezeigt.

Folgendes habe ich bisher

LinkedResource inline = new LinkedResource(filePath);
inline.ContentId = Guid.NewGuid().ToString();
MailMessage mail = new MailMessage();
Attachment att = new Attachment(filePath);
att.ContentDisposition.Inline = true;
mail.From = from_email;
mail.To.Add(data.email);
mail.Subject = "Client: " + data.client_id + " Has Sent You A Screenshot";
mail.Body = String.Format(
    "<h3>Client: " + data.client_id + " Has Sent You A Screenshot</h3>" +
    @"<img src=""cid:{0}"" />", inline.ContentId);

mail.IsBodyHtml = true;
mail.Attachments.Add(att);
c# image email smtp inline Tsukasa
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1
Sie hängen die LinkedResource nicht an das E-Mail-Objekt an. Stattdessen erstellen Sie es, fügen dann aber ein separates Anhangsobjekt hinzu.
Adrian Wragg
4
Das einzige Problem mit diesem Code ist, dass Ihre Zeichenfolge.Format referenziert inline.ContentId, wann es eigentlich sein sollte att.ContentId. inlineist überhaupt nicht erforderlich. Ich ziehe Ihre Frage allen Antworten vor, da Sie wirklich keine verwenden müssen AlternateView.
Simon MᶜKenzie
Mögliches Duplikat von C #, das E-Mails mit Bildern inline mit SmtpClient sendet
Frédéric
Mein Bild wird als bin-Dateierweiterung angehängt. Mache ich etwas falsch?
Miloš Đošović
Überprüfen Sie diesen Link. Es ist einsatzbereit für mehrere Inline-Anhänge sowie für allgemeine Anhänge für PDF- / Excel-Dateien. stackoverflow.com/questions/33665280/…
Kumar Chandraketu

Antworten:

61

Versuche dies

 string htmlBody = "<html><body><h1>Picture</h1><br><img src=\"cid:filename\"></body></html>";
 AlternateView avHtml = AlternateView.CreateAlternateViewFromString
    (htmlBody, null, MediaTypeNames.Text.Html);

 LinkedResource inline = new LinkedResource("filename.jpg", MediaTypeNames.Image.Jpeg);
 inline.ContentId = Guid.NewGuid().ToString();
 avHtml.LinkedResources.Add(inline);

 MailMessage mail = new MailMessage();
 mail.AlternateViews.Add(avHtml);

 Attachment att = new Attachment(filePath);
 att.ContentDisposition.Inline = true;

 mail.From = from_email;
 mail.To.Add(data.email);
 mail.Subject = "Client: " + data.client_id + " Has Sent You A Screenshot";
 mail.Body = String.Format(
            "<h3>Client: " + data.client_id + " Has Sent You A Screenshot</h3>" +
            @"<img src=""cid:{0}"" />", att.ContentId);

 mail.IsBodyHtml = true;
 mail.Attachments.Add(att);
Microsoft DN
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25
Dieser Code funktioniert nicht. Verwenden Sie den folgenden Code von @ T30. Beachten Sie beim Hinzufügen einer alternativen Ansicht zu MailMessage, dass diese Ansicht der Hauptteil Ihrer E-Mail ist und Sie die Body-Eigenschaft NICHT ausfüllen müssen.
Eric
@ Eric: Es gab ein kleines Problem in diesem Code. in der mail.body verwenden Sie einfach att.ContentId anstelle von inline.ContentId
Amir
153

Ein minimaler C # -Code zum Einbetten eines Bildes kann sein:

MailMessage mailWithImg = getMailWithImg();
MySMTPClient.Send(mailWithImg); //* Set up your SMTPClient before!

private MailMessage getMailWithImg() {
    MailMessage mail = new MailMessage();
    mail.IsBodyHtml = true;
    mail.AlternateViews.Add(getEmbeddedImage("c:/image.png"));
    mail.From = new MailAddress("yourAddress@yourDomain");
    mail.To.Add("recipient@hisDomain");
    mail.Subject = "yourSubject";
    return mail;
}
private AlternateView getEmbeddedImage(String filePath) {
    LinkedResource res = new LinkedResource(filePath);
    res.ContentId = Guid.NewGuid().ToString();
    string htmlBody = @"<img src='cid:" + res.ContentId + @"'/>";
    AlternateView alternateView = AlternateView.CreateAlternateViewFromString(htmlBody, null, MediaTypeNames.Text.Html);
    alternateView.LinkedResources.Add(res);
    return alternateView;
}
T30
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3
Ich musste dem einen MIME-Typ hinzufügen LinkedResource, damit er im Webclient von Hotmail / Outlook.com funktioniert. FWIW, ich habe dies ebenso versucht wie @Microsoft DN und dies hat besser funktioniert.
Gregtheross
3
Für mich funktioniert es, aber ich musste den ContentType hinzufügen: LinkedResource inline = new LinkedResource (filePath, MediaTypeNames.Image.Jpeg);
Washington da Costa
5
Kleiner Kommentar: Kein Aufruf erforderlich NewGuid(), die AttachmentBaseKlasse (die von LinkedResourceerbt) erstellt ihn bei Bedarf bereits.
Andrew
1
Fügen Sie der LinkedResource den ContentType "image / bmp" hinzu, damit das Bild nicht als angehängte Datei empfangen wird.
Tanner Ornelas
1
@ WilliamHumphries Ich denke, der Garbage Collector kümmert sich bereits darum.
T30
9 
    protected void Page_Load(object sender, EventArgs e)
    {
        string Themessage = @"<html>
                          <body>
                            <table width=""100%"">
                            <tr>
                                <td style=""font-style:arial; color:maroon; font-weight:bold"">
                               Hi! <br>
                                <img src=cid:myImageID>
                                </td>
                            </tr>
                            </table>
                            </body>
                            </html>";
        sendHtmlEmail("[email protected]", "tomailaccount", Themessage, "Scoutfoto", "Test HTML Email", "smtp.gmail.com", 25);
    }

    protected void sendHtmlEmail(string from_Email, string to_Email, string body, string           from_Name, string Subject, string SMTP_IP, Int32 SMTP_Server_Port)
    {
        //create an instance of new mail message
        MailMessage mail = new MailMessage();

        //set the HTML format to true
        mail.IsBodyHtml = true;

        //create Alrternative HTML view
        AlternateView htmlView = AlternateView.CreateAlternateViewFromString(body, null, "text/html");

        //Add Image
        LinkedResource theEmailImage = new LinkedResource("E:\\IMG_3332.jpg");
        theEmailImage.ContentId = "myImageID";

        //Add the Image to the Alternate view
        htmlView.LinkedResources.Add(theEmailImage);

        //Add view to the Email Message
        mail.AlternateViews.Add(htmlView);

        //set the "from email" address and specify a friendly 'from' name
        mail.From = new MailAddress(from_Email, from_Name);

        //set the "to" email address
        mail.To.Add(to_Email);

        //set the Email subject
        mail.Subject = Subject;

        //set the SMTP info
        System.Net.NetworkCredential cred = new System.Net.NetworkCredential("[email protected]", "fromEmail password");
        SmtpClient smtp = new SmtpClient("smtp.gmail.com", 587);
        smtp.EnableSsl = true;
        smtp.DeliveryMethod = SmtpDeliveryMethod.Network;
        smtp.UseDefaultCredentials = false;
        smtp.Credentials = cred;
        //send the email
        smtp.Send(mail);
    }
Deepak Gour
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5

Ein noch minimalistischeres Beispiel:

var linkedResource = new LinkedResource(@"C:\Image.jpg", MediaTypeNames.Image.Jpeg);

// My mail provider would not accept an email with only an image, adding hello so that the content looks less suspicious.
var htmlBody = $"hello<img src=\"cid:{linkedResource.ContentId}\"/>";
var alternateView = AlternateView.CreateAlternateViewFromString(htmlBody, null, MediaTypeNames.Text.Html);
alternateView.LinkedResources.Add(linkedResource);

var mailMessage = new MailMessage
{
    From = new MailAddress("[email protected]"),
    To = { "[email protected]" },
    Subject = "yourSubject",
    AlternateViews = { alternateView }
};

var smtpClient = new SmtpClient();
smtpClient.Send(mailMessage);
Oskar Sjöberg
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4

Zusätzlich zu den obigen Kommentaren habe ich die folgenden zusätzlichen Kommentare:

  • Mischen Sie nicht Anhänge und AlternativeView, die Verwendung von oder die andere. Wenn Sie sie mischen, werden die Inline-Anhänge als unbekannte Downloads gerendert.
  • Während Outlook und Google den Standard-HTML-Stil zulassen, "cid:att-001"funktioniert dies NICHT auf dem iPhone (Patch-Level Ende 2016), sondern es wird eine reine alphanumerische Zahl verwendet"cid:att-001" -> "cid:att001"

Nebenbei. Das Rendern von Outlook (auch Office 2015) (immer noch die klare Mehrheit für Geschäftsbenutzer) erfordert die Verwendung von HTML im TABLE TR TD-Stil, da es das HTML-Box-Modell nicht vollständig unterstützt.

Guy Langston
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Großartig, ich bin beeindruckt von Ihrer Forschung.
Hammad Sajid
Dies ist im Jahr 2020 immer noch der Fall. Ich musste lediglich den gesamten LinkedResource / AlternativeView-Code durch den Anhangscode ersetzen, da ich auch Dateianhänge benötigte. Dieser Beitrag scheint das einzige im gesamten Internet zu sein, das erwähnt, dass dies nicht funktioniert
Whelkaholism
3

Versuche dies.

protected void Page_Load(object sender, EventArgs e)
        {
            string Themessage = @"<html>
                              <body>
                                <table width=""100%"">
                                <tr>
                                    <td style=""font-style:arial; color:maroon; font-weight:bold"">
                                   Hi! <br>
                                    <img src=cid:myImageID>
                                    </td>
                                </tr>
                                </table>
                                </body>
                                </html>";
            sendHtmlEmail("[email protected]", "tomailaccount", Themessage, "Scoutfoto", "Test HTML Email", "smtp.gmail.com", 25);
        }
protected void sendHtmlEmail(string from_Email, string to_Email, string body, string from_Name, string Subject, string SMTP_IP, Int32 SMTP_Server_Port)
        {
            //create an instance of new mail message
            MailMessage mail = new MailMessage();

            //set the HTML format to true
            mail.IsBodyHtml = true;

            //create Alrternative HTML view
            AlternateView htmlView = AlternateView.CreateAlternateViewFromString(body, null, "text/html");

            //Add Image
            LinkedResource theEmailImage = new LinkedResource("E:\\IMG_3332.jpg");
            theEmailImage.ContentId = "myImageID";

            //Add the Image to the Alternate view
            htmlView.LinkedResources.Add(theEmailImage);

            //Add view to the Email Message
            mail.AlternateViews.Add(htmlView);

            //set the "from email" address and specify a friendly 'from' name
            mail.From = new MailAddress(from_Email, from_Name);

            //set the "to" email address
            mail.To.Add(to_Email);

            //set the Email subject
            mail.Subject = Subject;

            //set the SMTP info
            System.Net.NetworkCredential cred = new System.Net.NetworkCredential("[email protected]", "fromEmail password");
            SmtpClient smtp = new SmtpClient("smtp.gmail.com", 587);
            smtp.EnableSsl = true;
            smtp.DeliveryMethod = SmtpDeliveryMethod.Network;
            smtp.UseDefaultCredentials = false;
            smtp.Credentials = cred;
            //send the email
            smtp.Send(mail);
        }
Deepak Gour
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1

Sie müssen die LinkedResource einer AlternateView hinzufügen

AlternateView alternateView = AlternateView.CreateAlternateViewFromString("<h3>Client: " + data.client_id + " Has Sent You A Screenshot</h3>" +
                @"<img src=""cid:{0}"" />", null, "text/html");
alternateView.LinkedResources.Add(inline);
mail.AlternateViews.Add(alternateView);
Giannis Paraskevopoulos
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1 
    MailMessage mail = new MailMessage();
    //set the addresses
    mail.From = new MailAddress("[email protected]");
    mail.To.Add("[email protected]");

    //set the content
    mail.Subject = "Sucessfully Sent the HTML and Content of mail";

    //first we create the Plain Text part
    string plainText = "Non-HTML Plain Text Message for Non-HTML enable mode";
    AlternateView plainView = AlternateView.CreateAlternateViewFromString(plainText, null, "text/plain");
    XmlTextReader reader = new XmlTextReader(@"E:\HTMLPage.htm");
    string[] address = new string[30];
    string finalHtml = "";
    var i = -1;
    while (reader.Read())
    {
        if (reader.NodeType == XmlNodeType.Element)
        { // The node is an element.
            if (reader.AttributeCount <= 1)
            {
                if (reader.Name == "img")
                {
                    finalHtml += "<" + reader.Name;
                    while (reader.MoveToNextAttribute())
                    {
                        if (reader.Name == "src")
                        {
                            i++;
                            address[i] = reader.Value;
                            address[i] = address[i].Remove(0, 8);
                            finalHtml += " " + reader.Name + "=" + "cid:chartlogo" + i.ToString();
                        }
                        else
                        {
                            finalHtml += " " + reader.Name + "='" + reader.Value + "'";
                        }
                    }
                    finalHtml += ">";
                }
                else
                {
                    finalHtml += "<" + reader.Name;
                    while (reader.MoveToNextAttribute())
                    {
                        finalHtml += " " + reader.Name + "='" + reader.Value + "'";
                    }
                    finalHtml += ">";
                }
            }

        }
        else if (reader.NodeType == XmlNodeType.Text)
        { //Display the text in each element.
            finalHtml += reader.Value;
        }
        else if (reader.NodeType == XmlNodeType.EndElement)
        {
            //Display the end of the element.
            finalHtml += "</" + reader.Name;
            finalHtml += ">";
        }

    }

    AlternateView htmlView = AlternateView.CreateAlternateViewFromString(finalHtml, null, "text/html");
    LinkedResource[] logo = new LinkedResource[i + 1];
    for (int j = 0; j <= i; j++)
    {
        logo[j] = new LinkedResource(address[j]);
        logo[j].ContentId = "chartlogo" + j;
        htmlView.LinkedResources.Add(logo[j]);
    }
    mail.AlternateViews.Add(plainView);
    mail.AlternateViews.Add(htmlView);
    SmtpClient smtp = new SmtpClient();
    smtp.Host = "smtp.gmail.com";
    smtp.Port = 587;
    smtp.Credentials = new NetworkCredential(
        "[email protected]", "Password");
    smtp.EnableSsl = true;
    Console.WriteLine();
    smtp.Send(mail);
}
Amit Bidwai
quelle
1

Die andere Lösung besteht darin, das Bild als Anhang anzuhängen und dann mit cid auf den HTML-Code zu verweisen. HTML Quelltext:

<html>
<head>
</head>
<body>
    <img width=100 height=100 id=""1"" src=""cid:Logo.jpg"">
</body>
</html>

C # -Code:

EmailMessage email = new EmailMessage(service);
email.Subject = "Email with Image";
email.Body = new MessageBody(BodyType.HTML, html);
email.ToRecipients.Add("[email protected]");
string file = @"C:\Users\acv\Pictures\Logo.jpg";
email.Attachments.AddFileAttachment("Logo.jpg", file);
email.Attachments[0].IsInline = true;
email.Attachments[0].ContentId = "Logo.jpg";
email.SendAndSaveCopy();
Khyati Elhance
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0

Senden von 2 Bildern vb.net Code-Konvertierung für C # Online-Konverter.

Public Function SendEmail(Optional ByVal p_AsHTML As Boolean = False, Optional ByVal p_themEmail As String = "") As Boolean
            Dim client As SmtpClient = New SmtpClient ''("FMSERVER.FMINNOVATIONS.COM.AU")
            'Dim fromAddress As MailAddress = New MailAddress(Me.FromEmail, "WSMenterprise")
            'Dim toAddress As MailAddress
            Try
                Dim aMessage As New MailMessage()
                '(New MailAddress(Me.FromEmail, "WSMenterprise"), New MailAddress(anAdd))
                If _fromAddress IsNot Nothing Then
                    If _fromName IsNot Nothing Then
                        aMessage.From = New MailAddress(_fromAddress, _fromName)
                    Else
                        aMessage.From = New MailAddress(_fromAddress)
                    End If
                End If
                For Each anAdd As String In _To
                    aMessage.To.Add(New MailAddress(anAdd))
                Next
                For Each cc As String In _CC
                    aMessage.CC.Add(New MailAddress(cc))
                Next
                For Each bcc As String In _BCC
                    aMessage.Bcc.Add(New MailAddress(bcc))
                Next
                aMessage.Subject = _Subject
                aMessage.IsBodyHtml = p_AsHTML

                If _EmailLogo Is Nothing Then
                    aMessage.Body = _Body
                Else
                    If p_themEmail.ToString().ToLower.Contains("dexus") Then

                       Dim htmlView = AlternateView.CreateAlternateViewFromString(_Body.ToString(), Nothing, "text/html")
                        Dim logo As New LinkedResource(_EmailLogo)
                        logo.ContentId = "Dexuslogo1"
                        Dim logo1 As New LinkedResource(_EmailLogo1)
                        logo1.ContentId = "Dexuslogo2"
                        htmlView.LinkedResources.Add(logo)
                        htmlView.LinkedResources.Add(logo1)
                        aMessage.AlternateViews.Add(htmlView)

                    Else

                        Dim htmlView = AlternateView.CreateAlternateViewFromString(_Body.ToString(), Nothing, "text/html")
                        Dim logo As New LinkedResource(_EmailLogo)
                        logo.ContentId = "companylogo"
                        htmlView.LinkedResources.Add(logo)
                        aMessage.AlternateViews.Add(htmlView)
                    End If
                End If

                For Each anAttach As Attachment In _Attachments
                    aMessage.Attachments.Add(anAttach)
                Next

                If _ReplyTo IsNot Nothing Then aMessage.ReplyToList.Add(New MailAddress(_ReplyTo))
                client.Host = "smtpi.cbre.com.au"
                client.UseDefaultCredentials = True
                client.Send(aMessage)
            Catch exRecipUnk As SmtpFailedRecipientException
                Return False
            Catch exSmtp As SmtpException
                ''exSmtp.StatusCode
                Return False
            Catch ex As Exception
                Return False
            End Try
            Return True
        End Function
    If p_Gmap_code = "DE" Then
                Dim p_Theme As New Theme("Dexus")
                Dim passwordlink As String = ""
                Dim DexuslogoImage1 As String = System.IO.Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "Images\Dexus_Notice_Logo.png")
                Dim DexuslogoImage2 As String = System.IO.Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "Images\DexusTenantNotice.png")

                passwordlink = "<a href='" + p_Theme.TenantLoginPage + "?accesstype=email&te=" + a.Encrypt(p_TenantEmail) + "' target='_blank'>here.</a><br/>"
                bodys += "<div align='Center'><table border='0' cellpadding='0' cellspacing='0'><tr style='height:50px;'><td width='623px' ></td><td valign='top' width='180'><p align='right'><a href='http://www.dexus.com/'><img border='0' height='50' src=cid:Dexuslogo1 width='174' alt=''/></a></p></td></tr><tr><td colspan='2' width='803' style='height:25px;'></td></tr> <tr><td width='623px'><p align='left' style='font-family:Arial;font-size:14pt;'><strong> Your Dexus Response Password is about to expire</strong></p></td>"
                bodys += " <td width='180'><p align='right' style='font-family:Arial;font-size:10pt;'>" + DateTime.Now.ToString("dd/MM/yyyy") + " </p>"
                bodys += "</td></tr><tr><td colspan='2' width='803' style='height:30px;'>  </td></tr> <tr>  <td colspan='2' width='803' style='font-family:Arial;font-size:10pt;'>"
                bodys += "<p>" + wishes + " " + p_TenantName.Trim().ToString() + "</p>"
                bodys += "</td></tr><tr><td colspan='2' width='803' style='height:25px;'></td> </tr><tr><td colspan='2' width='803' style='font-family:Arial;font-size:10pt;'>"
                bodys += "Your Dexus Response password is about to expire in " + p_remaindays.ToString() + " days.<br /><br /> To reset your password and update your details, please click " + passwordlink.ToString() + "<br /><br />Please note that if you do not update your password by " + p_date + ",then your account will be set to inactive and you will not be able to access Dexus Response.</br></br>Please contact Dexus Response if you require assistance in accessing the portal.</p></td>" 'edit
                bodys += " </tr><tr><td colspan='2' width='803' style='height:30px;'></td></tr><tr><td colspan='2' width='803'><table align='left' border='0' cellpadding='0' cellspacing='0'><tr><td width='802' style='font-family:Arial;font-size:10pt;'><p><strong>Dexus Response</strong></p></td></tr><tr><td width='802' style='font-family:Arial;font-size:10pt;'><p><a href='mailto:[email protected]'>[email protected]</a> <strong>|</strong> 1300 339 870 <strong>|</strong> <a href='https://response.dexus.com/'>response.dexus.com</a></p></td></tr></table></td></tr><tr><td colspan='2' width='803' style='height:15px;'></td></tr><tr> <td colspan='2' width='803'><p> </p><p><a href='https://response.dexus.com/' border='0' target='_blank'><img border='0' height='133'"
                bodys += "src=cid:Dexuslogo2 alt='' width='800' /></a></p></td></tr><tr><td colspan='2' width='803' style='height:10px;'></td></tr><tr><td colspan='2' width='803' style='font-family:Arial;font-size:10pt;'><p><a href='http://www.dexus.com/who-we-are/terms-and-conditions' style=' color:#000000;'>Terms and Conditions</a><strong> | </strong><a href='http://www.dexus.com/who-we-are/privacy-policy' style=' color:#000000;'> Privacy Policy</a></p></td></tr><tr><td colspan='2' width='803' style='height:40px;'></td></tr><tr><td colspan='2' width='803'><p></p></td></tr><tr><td colspan='2' width='803' style='height:10px;'></td></tr><tr></tr><tr><td colspan='2' width='803' style='height:20px;'></td></tr></table></div>"

                email = New Common.Email(emailHeading, bodys, p_Theme.EmailFrom, DexuslogoImage1, DexuslogoImage2)
                email.ToEmail = p_TenantEmail
                email.SendEmail(True, p_Theme.EmailFrom)

quelle
0

Wir haben alle unsere bevorzugten Codierungsstile. Das habe ich getan:

var pictures = new[]
{
    new { id = Guid.NewGuid(), type = "image/jpeg", tag = "justme", path = @"C:\Pictures\JustMe.jpg" },
    new { id = Guid.NewGuid(), type = "image/jpeg", tag = "justme-bw", path = @"C:\Pictures\JustMe-BW.jpg" }
}.ToList();

var content = $@"
<style type=""text/css"">
    body {{ font-family: Arial; font-size: 10pt; }}
</style>
<body>
<h4>{DateTime.Now:dddd, MMMM d, yyyy h:mm:ss tt}</h4>
<p>Some pictures</p>
<div>
    <p>Color Picture</p>
    <img src=cid:{{justme}} />
</div>
<div>
    <p>Black and White Picture</p>
    <img src=cid:{{justme-bw}} />
</div>
<div>
    <p>Color Picture repeated</p>
    <img src=cid:{{justme}} />
</div>
</body>
";

// Update content with picture guid
pictures.ForEach(p => content = content.Replace($"{{{p.tag}}}", $"{p.id}"));
// Create Alternate View
var view = AlternateView.CreateAlternateViewFromString(content, Encoding.UTF8, MediaTypeNames.Text.Html);
// Add the resources
pictures.ForEach(p => view.LinkedResources.Add(new LinkedResource(p.path, p.type) { ContentId = p.id.ToString() }));

using (var client = new SmtpClient()) // Set properties as needed or use config file
using (MailMessage message = new MailMessage()
{
    IsBodyHtml = true,
    BodyEncoding = Encoding.UTF8,
    Subject = "Picture Email",
    SubjectEncoding = Encoding.UTF8,
})
{
    message.AlternateViews.Add(view);
    message.From = new MailAddress("[email protected]");
    message.To.Add(new MailAddress("[email protected]"));
    client.Send(message);
}
JohnnyIV
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0

Ich habe den vollständigen Code unten hinzugefügt, um Bilder in Google Mail, Thunderbird und anderen E-Mail-Clients anzuzeigen: 

MailMessage mailWithImg = getMailWithImg();
MySMTPClient.Send(mailWithImg); //* Set up your SMTPClient before!

private MailMessage getMailWithImg()
{
    MailMessage mail = new MailMessage();
    mail.IsBodyHtml = true;
    mail.AlternateViews.Add(getEmbeddedImage("c:/image.png"));
    mail.From = new MailAddress("yourAddress@yourDomain");
    mail.To.Add("recipient@hisDomain");
    mail.Subject = "yourSubject";
    return mail;
}
private AlternateView getEmbeddedImage(String filePath)
 {
    // below line was corrected to include the mediatype so it displays in all 
    // mail clients. previous solution only displays in Gmail the inline images 
    LinkedResource res = new LinkedResource(filePath, MediaTypeNames.Image.Jpeg);  
    res.ContentId = Guid.NewGuid().ToString();
    string htmlBody = @"<img src='cid:" + res.ContentId + @"'/>";
    AlternateView alternateView = AlternateView.CreateAlternateViewFromString(htmlBody,  
     null, MediaTypeNames.Text.Html);
    alternateView.LinkedResources.Add(res);
    return alternateView;
}
Kennzeichen
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