B4X

Add a Related String Resource to an Email

Demonstrates the Chilkat Email.AddRelatedString method, which adds a text-based related MIME resource, such as a style sheet, from an in-memory string and returns the generated Content-ID. The first argument is the MIME resource name, the second is the text content, and the third is the charset used to encode it. Because the Content-ID is generated by the call, this example adds the style sheet first, then builds an HTML body in a StringBuilder that references the style sheet by that cid:, and passes the result to SetHtmlBody.

Background: Related items are not always images loaded from disk — sometimes the resource is text you already have in memory, like a generated CSS style sheet or an SVG. AddRelatedString lets you embed such content directly without writing a temporary file first. As with other related items, it lives in the multipart/related enclosure and is referenced from the HTML by the Content-ID the method returns.

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'  Demonstrates the AddRelatedString method, which adds a text-based related MIME resource
'  (such as a style sheet) from an in-memory string and returns the generated Content-ID.
'  The first argument is the resource name, the second is the text content, the third is the charset.

Dim email As ChilkatEmail
email.Initialize
email.Subject = "Email with a related style sheet"

'  Add the text-based related resource first; capture the generated Content-ID.
Dim cid As String = email.AddRelatedString("styles.css", "body { color: navy; }", "utf-8")
If email.LastMethodSuccess = False Then
    Log(email.LastErrorText)
    Return
End If


'  Build the HTML body, referencing the related style sheet by its Content-ID.  A
'  placeholder is used and then replaced with the actual Content-ID.
Dim sbHtml As ChilkatStringBuilder
sbHtml.Initialize
sbHtml.Append("<html><head><link rel=" & Chr(34) & "stylesheet" & Chr(34) & " href=" & Chr(34) & "cid:PLACEHOLDER_CID" & Chr(34) & "/></head><body>Styled content.</body></html>")
Dim numReplaced As Int = sbHtml.Replace("PLACEHOLDER_CID", cid)
email.SetHtmlBody(sbHtml.GetAsString)

Log("Related Content-ID = " & cid)
Log("NumRelatedItems = " & email.NumRelatedItems)