To support this rendering mechanism, a source must be able to receive and process the following messages:

• WM_DDE_REQUEST

  This message is posted by the target to the window indicated by the hwndItem field in the DRAGITEM data structure to request information regarding the object. Note that WM_DDE_INITIATE is not required because the target already has the handle of the window it wants to converse with. This message is sent for all Move and Copy operations.

• WM_DDE_ADVISE

  This message is posted by the target to the window indicated by the hwndItem field in the DRAGITEM data structure order to maintain a hot link to the object.

• WM_DDE_UNADVISE

  This message is posted by the target to the window indicated by the hwndItem field in the DRAGITEM data structure to terminate a hot link to the object.

• WM_DDE_TERMINATE

  This message is posted by the target to the window indicated by the hwndItem field in the DRAGITEM data structure to terminate a conversation.

To support this rendering mechanism, a target must be able to receive and process the following messages:

• WM_DDE_DATA

  This message is posted to the target by the source to deliver the requested information regarding the object.

• WM_DDE_ACK

  This message is posted to the target by the source to acknowledge a WM_DDE_ADVISE or WM_DDE_UNADVISE message.

• WM_DDE_TERMINATE

  This message is posted to the target by the source to end a conversation.