B4X
Send HTML Email with External CSS as Related Item

Demonstrates how to compose an HTML email with an external CSS file included as a related item and referenced by CID (Content-ID).
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Dim success As Boolean = False

'  This example requires the Chilkat API to have been previously unlocked.
'  See Global Unlock Sample for sample code.

'  The mailman object is used for sending and receiving email.
Dim mailman As ChilkatMailMan
mailman.Initialize("mailman")

'  Use your SMTP server hostname.  This example uses office365, but it could be any SMTP server..
mailman.SmtpHost = "outlook.office365.com"
mailman.SmtpPort = 587
mailman.StartTLS = True

'  Set the SMTP login/password
mailman.SmtpUsername = "OFFICE365-SMTP-LOGIN"
mailman.SmtpPassword = "OFFICE365-SMTP-PASSWORD"

'  Create a new email object
Dim email As ChilkatEmail
email.Initialize
email.Subject = "HTML Email with embedded CSS"
email.From = "Chilkat Support <my-office365-user@mydomain.com>"
email.AddTo("Chilkat Support", "support@chilkatsoft.com")

Dim sbCss As ChilkatStringBuilder
sbCss.Initialize
Dim bCrlf As Boolean = True
sbCss.AppendLine("body {", bCrlf)
sbCss.AppendLine("    background-color: powderblue;", bCrlf)
sbCss.AppendLine("}", bCrlf)
sbCss.AppendLine("h1 {", bCrlf)
sbCss.AppendLine("    color: blue;", bCrlf)
sbCss.AppendLine("}", bCrlf)
sbCss.AppendLine("p {", bCrlf)
sbCss.AppendLine("    color: red;", bCrlf)
sbCss.AppendLine("}", bCrlf)

'  It's possible to add a CSS file directly by calling AddRelatedFile.
'  This example will add the CSS from a string.
Dim filenameInHtml As String = "styles.css"
Dim contentIdCss As String = email.AddRelatedString(filenameInHtml, sbCss.GetAsString, "utf-8")
If email.LastMethodSuccess <> True Then
    Log(email.LastErrorText)
    Return
End If


'  The src attribute for the image tag is set to the contentIdCss:
Dim sbHtml As ChilkatStringBuilder
sbHtml.Initialize
sbHtml.AppendLine("<!DOCTYPE html>", bCrlf)
sbHtml.AppendLine("<html>", bCrlf)
sbHtml.AppendLine("<head>", bCrlf)
sbHtml.AppendLine("  <link rel=" & Chr(34) & "stylesheet" & Chr(34) & " href=" & Chr(34) & "cid:CONTENT_ID_CSS" & Chr(34) & ">", bCrlf)
sbHtml.AppendLine("</head>", bCrlf)
sbHtml.AppendLine("<body>", bCrlf)
sbHtml.AppendLine("", bCrlf)
sbHtml.AppendLine("<h1>This is a heading</h1>", bCrlf)
sbHtml.AppendLine("<p>This is a paragraph.</p>", bCrlf)
sbHtml.AppendLine("", bCrlf)
sbHtml.AppendLine("</body>", bCrlf)
sbHtml.AppendLine("</html>", bCrlf)

Dim numReplacements As Int = sbHtml.Replace("CONTENT_ID_CSS", contentIdCss)

email.SetHtmlBody(sbHtml.GetAsString)

success = mailman.SendEmail(email)
If success <> True Then
    Log(mailman.LastErrorText)
Else
    Log("Mail Sent!")
End If