Sets the relation_type property to relation_type
such as GCONTACT_WEBSITE_HOME_PAGE or
GCONTACT_WEBSITE_FTP.
If relation_type is null, the relation type will be unset. When the
GContactWebsite is used in a query, however, exactly one of
relation_type and
label must be null.
| this | |
| relation_type |
the new relation type for the website |