DDE Functions

See Also

Exchange data between Visual FoxPro and other Microsoft Windows-based applications.

Remarks

Visual FoxPro can act as both a server and a client to send and receive data to and from other Microsoft Windows-based applications.

The following naming conventions are used in applications that support DDE (dynamic data exchange).

Name Description
Service Name A name that the server responds to when a client tries to access the server. A server can support many service names.
Topic Name A name that specifies a logical set of data. For file-based applications, topic names are usually file names. In other applications, topic names are application-specific. To access the server, the client must specify a topic name in addition to the server's service name.
Item Name A name that specifies a unit of data that the server can pass to the client requesting the data.

To request data from another application, create a Visual FoxPro program that establishes Visual FoxPro as a client. Here is a brief outline for creating a simple Visual FoxPro program that requests data from another application:

The functions above establish a cold link. A cold link exists when the client initiates all the communications between the applications. For a discussion of other types of links, see DDEAdvise( ).

The following is a brief outline for a program that establishes Visual FoxPro as a server:

Note that these DDE functions differ from previous Visual FoxPro function conventions in the following ways:

DDE Function Description
DDEAbortTrans( ) Ends an asynchronous DDE transaction.
DDEAdvise( ) Creates a notify link or an automatic link used in DDE.
DDEEnabled( ) Enables or disables DDE processing or returns the status of DDE processing.
DDEExecute( ) Using DDE, sends a command to another application.
DDEInitiate( ) Establishes a DDE channel between Visual FoxPro and another Microsoft Windows-based application.
DDELastError( ) Returns an error number for the last DDE function.
DDEPoke( ) Sends data between client and server applications in a DDE conversation.
DDERequest( ) Requests data from a server application in a dynamic DDE conversation.
DDESetOption( ) Changes or returns DDE settings.
DDESetService( ) Creates, releases, or modifies service names and settings in Visual FoxPro.
DDESetTopic( ) In a DDE conversation, creates or releases a topic name from a service name.
DDETerminate( ) Closes a DDE channel established with DDEInitiate( ).