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Chapter 11

Dynamic Data Exchange (DDE) Functions

Dynamic Data Exchange (DDE) is a method of transferring data between two Windows applications while they are running.

A DDE conversation is initiated by the DDE client, in this case the iProcess Workspace (Windows), by sending a message to the DDE server, for instance an application from which data is being requested, or which is being instructed to perform some task like opening an image window.

DDE facilities are mainly used in scripts, since multiple DDE statements are usually necessary for each interaction.

The Initiate Conversation message is sent with the DDEINITIATE script statement. This is followed by one or more messages such as DDEREQUEST, DDEEXECUTE or DDEGETTOPIC. The conversation is terminated with DDETERMINATE (or DDETERMALL).

For example:

 

   WINRUN ("C:\Program Files\Microsoft Office\Office10\EXCEL.exe C:\BUDG.XLS", 1)

 

   init := DDEINITIATE (excelch, "EXCEL", "c:\BUDG.XLS")

   req := DDEREQUEST (excelch, "R4C6", field1, 1, 5)

   exec := DDEPOKE (excelch, "R1C2", "Hello", 5)

   term := DDETERMINATE (excelch)

where excelch and field1 are iProcess fieldnames.

In this example, iProcess Workspace (Windows) establishes a DDE conversation with Excel, instructs Excel to open the BUDG.XLS spreadsheet, and then retrieves the value of a particular cell into an iProcess field.

All DDE commands are performed synchronously - iProcess waits until the command completes before continuing.

The following DDE functions can be used.

 

Function	Usage	Description	See
DDEEXECUTE	ge	Send an EXECUTE command to a server	page 137
DDEGETNAME		Get a DDE server's application name	page 138
DDEGETTOPIC		Get a DDE server's topic name	page 139
DDEINITIATE		Initiate a conversation with a DDE server	page 140
DDEPOKE		Send data to a server	page 142
DDEREQUEST		Request an item of data from a server	page 143
DDETERMALL		Terminate all DDE conversations	page 145
DDETERMINATE		Terminate a DDE conversation	page 146

Copyright © Cloud Software Group, Inc. All Rights Reserved