Appending to an email body

Here is a C# example to append more text to an email’s body:

    Chilkat.Email email = new Chilkat.Email();

    bool success = email.LoadEml("in.eml");
    if (!success)
    {
        textBox1.Text = email.LastErrorText;
        return;
    }

    // Does this email have a plain-text body?
    if (email.HasPlainTextBody())
    {
        string s = email.GetPlainTextBody();
        s += "\r\nMore text appended to the email's plain-text body.";
        // Replace the plain-text body:
        if (email.HasHtmlBody())
        {
            // This is an email with both plain-text and HTML alternatives
            // The AddPlainTextAlternative body replaces the plain-text body if it already exists.
            email.AddPlainTextAlternativeBody(s);
        }
        else
        {
            // This is a plain-text only email.
            email.Body = s;
        }
    }

    if (email.HasHtmlBody())
    {
        string s = email.GetHtmlBody();
        s += "<p>More text appended to the email's plain-text body.</p>";
        // Replace the HTML body:
        if (email.HasPlainTextBody())
        {
            // This is an email with both plain-text and HTML alternatives
            // The AddHtmlAlternativeBody replaces the HTML body if it already exists.
            email.AddHtmlAlternativeBody(s);
        }
        else
        {
            // This is an HTML-only email.
            email.SetHtmlBody(s);
        }
    }

    email.SaveEml("out.eml");