Using OLE to Perform Standard DDE Operations (74801)

This article was previously published under Q74801

In general, the OLE libraries can be used to perform the same types of operations as the Dynamic Data Exchange Management Library (DDEML). With the OLE libraries, an application can:

• Initialize conversations based on application and topic names or wild cards
• Request data for named items in negotiated formats from a server
• Establish an advise loop, (that is, request that a server notify the client of changes to the values of specified items, and optionally send the data when the change occurs)
• Send data from a server to a client
• Poke data from a client to a server
• Send a command (execute string) to the server

To get an idea of how these operations are performed using the OLE libraries, review the OLE library API. Except for sending commands, the OLE API was designed with embedded and linked objects in mind; however, OLE is applicable to traditional, nonpersistent DDE items.

Because DDE execute strings are outside of the realm of the OLE protocol, a special API has been provided. The OleExecute function in OLECLI (the OLE client library) enables an application to send a DDE execute command with an arbitrary command string. The server responds to this command using the Execute method defined in the OLEDOCUMENTVTBL structure.