Using Dynamic Data Exchange

Dynamic data exchange (DDE) is a mechanism that permits two applications to communicate by automatically and continuously exchanging data. Many applications that don't yet support OLE Automation support DDE. To run a DDE conversation between applications, you establish a channel, select a topic, request and send data, and then close the channel when you finish exchanging data. The following table lists the tasks that Microsoft Excel performs with DDE and the method used for each task.

Task	Method

Starting DDE	DDEInitiate
Getting text from another application	DDERequest
Sending text to another application	DDEPoke
Carrying out a command in another application	DDEExecute
Ending DDE	DDETerminate

Note

Not all applications support DDE. To find out whether an application supports DDE, see the documentation for that application.

The following procedure uses most of the DDE calls explained in the preceding table. The DemoDDE() procedure places the text string "I'm here" in cell A1 on Sheet1 of the active workbook.

Sub DemoDDE()
    Set dataCell = ActiveWorkbook.Worksheets("Sheet1").Range("A1")
    dataCell.Value = "I'm here!"
    ChannelNumber = Application.DDEInitiate("DDE", "Form1")
    Application.DDEPoke ChannelNumber, "Text1", dataCell
    Application.DDETerminate ChannelNumber
End Sub