Add a Related String Resource to an Email

See more Email Object Examples

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.

Chilkat C Downloads

Download Chilkat for C

#include <C_CkEmail.h>
#include <C_CkStringBuilder.h>

void ChilkatSample(void)
    {
    HCkEmail email;
    const char *cid;
    HCkStringBuilder sbHtml;
    int numReplaced;

    //  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.

    email = CkEmail_Create();
    CkEmail_putSubject(email,"Email with a related style sheet");

    //  Add the text-based related resource first; capture the generated Content-ID.
    cid = CkEmail_addRelatedString(email,"styles.css","body { color: navy; }","utf-8");
    if (CkEmail_getLastMethodSuccess(email) == FALSE) {
        printf("%s\n",CkEmail_lastErrorText(email));
        CkEmail_Dispose(email);
        return;
    }

    //  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.
    sbHtml = CkStringBuilder_Create();
    CkStringBuilder_Append(sbHtml,"<html><head><link rel=\"stylesheet\" href=\"cid:PLACEHOLDER_CID\"/></head><body>Styled content.</body></html>");
    numReplaced = CkStringBuilder_Replace(sbHtml,"PLACEHOLDER_CID",cid);
    CkEmail_SetHtmlBody(email,CkStringBuilder_getAsString(sbHtml));

    printf("Related Content-ID = %s\n",cid);
    printf("NumRelatedItems = %d\n",CkEmail_getNumRelatedItems(email));


    CkEmail_Dispose(email);
    CkStringBuilder_Dispose(sbHtml);

    }