The Size property returns the approximate size in bytes of the message. Read-only.
objMessage.Size
Long
The Size property contains the sum, in bytes, of the sizes of all properties on this Message object, including in particular the Attachments property. It can be considerably greater than the size of the Text property alone.
The Size property is computed by the message store and is not valid until after the first Update or Send operation. Note that not all message stores support this property.
AppointmentItem objects in a Microsoft® Schedule+ calendar folder do not have the full set of attributes of a general message. If you obtain the default calendar folder by passing CdoDefaultFolderCalendar to the Session object's GetDefaultFolder method, its appointments have no defined value for the Size property. An attempt to access Size in this case returns CdoE_NOT_FOUND.
The Size property corresponds to the MAPI property PR_MESSAGE_SIZE. It can be rendered into HTML hypertext using the CDO Rendering ObjectRenderer object. To specify this, set the object renderer's DataSource property to this Message object and the property parameter of the RenderProperty method to CdoPR_MESSAGE_SIZE.