property ContentType: string;
Holds the MIME media type of the message.
ContentType is intended to describe the data contained in the message body to allow a user agent to determine how to present the data.
Common values of ContentType include text/plain, text/html, text/xml, text/enhanced, image/jpeg, image/gif, audio/basic, audio/au, video/mpeg, application/octet-stream, application/postscript, application/ms-word, application/ms-excel, application/rtf, multipart/mixed, multipart/alternative, and message/external-body.
ContentType gets or sets the value of the "Content-Type" Internet Message header. When you change ContentType, the respective header in the Headers property is changed as well.