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Application.DDERequest Method

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Word Developer Reference

Uses an open dynamic data exchange (DDE) channel to request information from the receiving application, and returns the information as a String.

Syntax

expression.DDERequest(Channel, Item)

expression   A variable that represents an Application object. Optional.

Parameters

Name Required/Optional Data Type Description
Channel Required Long The channel number returned by the DDEInitiate method.
Item Required String The item to be requested.

Remarks

Security  Dynamic data exchange (DDE) is an older technology that is not secure. If possible, use a more secure alternative to DDE, such as object linking and embedding (OLE).

When you request information from the topic in the server application, you must specify the item in that topic whose contents you are requesting. In Microsoft Office Excel, for example, cells are valid items, and you refer to them by using either the "R1C1" format or named references.

Microsoft Excel and other applications that support DDE recognize a topic named "System." Three standard items in the System topic are described in the following table. Note that you can get a list of the other items in the System topic by using the SysItems item.

Item in System topic Effect
SysItems Returns a list of all the items in the System topic.
Topics Returns a list of all the available topics.
Formats Returns a list of all the Clipboard formats supported by Word.

Example

This example opens the Excel workbook Book1.xls and retrieves the contents of cell R1C1.

Visual Basic for Applications 
  Dim lngChannel As Long

lngChannel = DDEInitiate(App:="Excel", Topic:="System")
DDEExecute Channel:=lngChannel, Command:="[OPEN(" & Chr(34) _
& "C:\Documents\Book1.xls" & Chr(34) & ")]"
DDETerminate Channel:=lngChannel
lngChannel = DDEInitiate(App:="Excel", Topic:="Book1.xls")
MsgBox DDERequest(Channel:=lngChannel, Item:="R1C1")
DDETerminateAll

This example opens a channel to the System topic in Excel and then uses the Topics item to return a list of available topics. The example inserts the topic list, which includes all open workbooks, after the selection.

Visual Basic for Applications 
  Dim lngChannel As Long
Dim strTopicList As String

lngChannel = DDEInitiate(App:="Excel", Topic:="System")
strTopicList = DDERequest(Channel:=lngChannel, Item:="Topics")
Selection.InsertAfter strTopicList
DDETerminate Channel:=lngChannel

See Also