Question

我使用SmtpClient类使用C＃发送邮件。在发送邮件之前，我正在做以下事情。

var mailMessage = new MailMessage();

model.ToAddresses.ForEach(to => mailMessage.To.Add(to));
mailMessage.Subject = "Test Email - By Yasser";

mailMessage.Body = String.Format("{0}{1}{2}",
                                    "<html><body>",
                                     GetEmailContent(model),
                                     "</body></html>");
mailMessage.IsBodyHtml = true;
return MailService.SendEmail(mailMessage);

以下是我的MailService类：

public class MailService
{
    public static bool SendEmail(MailMessage mailMessage)
    {
        var smtpClient = new SmtpClient();
        try
        {
            smtpClient.Send(mailMessage);
            return true;
        }
        catch(Exception exp)
        {
            return false;
        }
    }
}

现在，当我发送邮件时，邮件会被发送，当我按下查看源时，这就是我在Outlook中看到的邮件内容。以下是带有查看源的电子邮件的内容（显然我只保留了部分图像数据）

<html>

<body>
    <h1>Test</h1>
    <h2>Hello World</h2>
    <h3>Missing close h3 tag</h3>

    <p>
        <a href="www.google.com">
            <img src="data:image/gif;base64,/9j/4AAQSkZJRgABAgEAYABgAAD/4Q8HRXhpZgAAT" />
        </a>
    </p>
</body>

</html>

所以这在邮件中看起来很破碎（图像），但是当我复制这个源并将其粘贴到编辑器中并使用浏览器打开文件时，一切看起来都很好（甚至是图像）。

更新：添加了来自outlook

的邮件图片

enter image description here

任何想法????

Answer 1

这是我尝试和工作的东西，在outlook，thunderbird和gmail中测试过。工作精细！

您可能想查看我提到的以下资源，以实现此目的：

示例代码：

// we need to use the prefix 'cid' in the img src value
string emailReadyHtml = string.empty;
emailReadyHtml += "<p>Hello World, below are two embedded images : </p>";
emailReadyHtml += "<img src=\"cid:yasser\" >";
emailReadyHtml += "<img src=\"cid:smile\" >";

MailMessage mailMessage = new MailMessage();

mailMessage.To.Add("yasser@mail.yy");
mailMessage.From = new MailAddress("info@mail.yy", "Info");

mailMessage.Subject = "Test Mail";
mailMessage.IsBodyHtml = true;

string image1Path = HttpContext.Current.Server.MapPath("~/Content/images/yasser.jpg");
byte[] image2Bytes = someArrayOfByte;

ContentType c = new ContentType("image/jpeg");

// create image resource from image path using LinkedResource class.
LinkedResource linkedResource1 = new LinkedResource(imagePath);
linkedResource1.ContentType = c ;
linkedResource1.ContentId = "yasser";
linkedResource1.TransferEncoding = TransferEncoding.Base64;

// the linked resource can be created from bytes also, which may be stored in database (which was my case)
LinkedResource linkedResource2 = new LinkedResource(new MemoryStream(image2Bytes));
linkedResource2.ContentType = c;
linkedResource2.ContentId = "smile";
linkedResource2.TransferEncoding = TransferEncoding.Base64;

AlternateView alternativeView = AlternateView.CreateAlternateViewFromString(emailReadyHtml, null, MediaTypeNames.Text.Html);

alternativeView.ContentId = "htmlView";
alternativeView.TransferEncoding = TransferEncoding.SevenBit;

alternativeView.LinkedResources.Add(linkedResource1) ;
alternativeView.LinkedResources.Add(linkedResource2);

mailMessage.AlternateViews.Add(alternativeView);

SmtpClient smtpClient = new SmtpClient();
smtpClient.Send(mailMessage);

Answer 2

这是一个可以解决问题的功能。在SendEmail之前调用它，如：

ProcessEmbeddingImages(mailMessage);
return MailService.SendEmail(mailMessage);

ProcessEmbeddingImages函数是用VB.Net编写的，因此您可能希望使用其中一个在线翻译器将其翻译为c＃。

Private Sub ProcessEmbeddingImages(ByRef oMail As System.Net.Mail.MailMessage)
    Dim oLinkedResources As New Hashtable()
    oMail.Body = PadSrcDataImage(oMail.Body, oLinkedResources)
    If oLinkedResources.Count > 0 Then

        Dim oAlternateView As System.Net.Mail.AlternateView = System.Net.Mail.AlternateView.CreateAlternateViewFromString(oMail.Body, Nothing, "text/html")
        oAlternateView.ContentId = "htmlView"
        oAlternateView.TransferEncoding = Net.Mime.TransferEncoding.SevenBit

        For Each oItem As DictionaryEntry In oLinkedResources
            Dim oKey As String() = Split(oItem.Key, "-")
            Dim i As Integer = oKey(0)
            Dim sExt As String = oKey(1)
            Dim sData As String = oItem.Value

            Dim oLinkedResource As New System.Net.Mail.LinkedResource(New IO.MemoryStream(System.Convert.FromBase64String(sData)))
            oLinkedResource.ContentId = "MyImg" & i
            oLinkedResource.TransferEncoding = Net.Mime.TransferEncoding.Base64
            oLinkedResource.ContentType = New System.Net.Mime.ContentType("image/" & sExt)
            oAlternateView.LinkedResources.Add(oLinkedResource)
        Next

        oMail.AlternateViews.Add(oAlternateView)
    End If
End Sub

Private Function PadSrcDataImage(ByVal sHtml As String, ByRef oLinkedResources As Hashtable) As String

    Dim oList As New ArrayList
    Dim sSearch As String = "\ssrc=['""]data:image/(.*?);base64,(.*?)['""]"

    Dim oMatches As System.Text.RegularExpressions.MatchCollection = System.Text.RegularExpressions.Regex.Matches(sHtml, sSearch, System.Text.RegularExpressions.RegexOptions.IgnoreCase)
    For Each m As System.Text.RegularExpressions.Match In oMatches
        If m.Groups.Count >= 2 Then
            Dim sExt As String = m.Groups(1).Value
            Dim sData As String = m.Groups(2).Value

            If sData.Length > 7 AndAlso Right(sData, 6) = "%3D%3D" Then
                'Replace trailing %3D%3D with ==
                sData = Left(sData, sData.Length - 6) & "=="
            End If

            oLinkedResources.Add(oLinkedResources.Count & "-" & sExt, sData)

            Dim iPos1 As Integer = m.Groups(1).Index - "data:image/".Length
            Dim iPos2 As Integer = m.Groups(2).Index + m.Groups(2).Length
            Dim iPoints As Integer() = {iPos1, iPos2}
            oList.Add(iPoints)
        End If
    Next

    Dim sRet As String = ""

    If oList.Count = 1 Then 'One img
        Dim iPoints As Integer() = oList(0)
        Dim sStr1 As String = sHtml.Substring(0, iPoints(0))
        Dim sStr2 As String = sHtml.Substring(iPoints(1))
        sRet = sStr1 & "cid:MyImg0" & sStr2

    ElseIf oList.Count > 1 Then

        For i As Integer = 0 To oList.Count - 1
            Dim iPoints As Integer() = oList(i)
            Dim iPos1 As Integer = iPoints(0)

            If i = 0 Then
                'First img
                Dim sStr1 As String = sHtml.Substring(0, iPos1)
                sRet += sStr1 & "cid:MyImg" & i

            Else 'Rest imgs
                Dim iPrevPos2 As Integer = oList(i - 1)(1)
                Dim sStr1 As String = sHtml.Substring(iPrevPos2, iPos1 - iPrevPos2)
                sRet += sStr1 & "cid:MyImg" & i

                If i = oList.Count - 1 Then    'Last
                    sRet += sHtml.Substring(iPoints(1))
                End If
            End If
        Next
    End If

    If sRet <> "" Then
        Return sRet
    Else
        Return sHtml
    End If
End Function

使用SmtpClient发送邮件时图像中断

2 个答案: