How to Use Network DDE

Last reviewed: August 5, 1996
Article ID: Q100363

The information in this article applies to:

Microsoft Windows Software Development Kit (SDK) version 3.1

SUMMARY

With Windows for Workgroups, an application can use Dynamic Data Exchange (DDE) over a network (NetDDE).

When using normal DDE or DDEML in an application, the various fields were set up as follows (using Excel as an example):

  APPLICATION       TOPIC     ITEM
  Excel             System     Topics

However, to start a DDE conversation over the network, a client application must establish the DDE conversation with another machine by specifying the following strings for the application name and topic

   application:   \\machine-name\NDDE$
   topic:           share-name

where the share name is defined in the [DDEShare] section of SYSTEM.INI. The default installation of Windows for Workgroups contains the following DDEShares:

   [DDEShares]
   HEARTS$=mshearts,hearts,,15,,0,,0,0,0
   CLPBK$=clipsrv,system,,31,,0,,0,0,0
   CHAT$=winchat,chat,,31,,0,,0,0,0

MORE INFORMATION

To illustrate how to use NetDDE, ClipBook will serve as a server example.

The following are specifics about ClipBook:

   Title Bar Caption    = ClipBook Viewer,
   Executable File Name = Clipbrd.exe,
   DDE Application Name = clipsrv,
   DDE Share Name       = CLPBK$

To start a conversation with ClipBook from your application, use the following strings:

   APPLICATION             TOPIC        ITEM
   \\machine-name\NDDE$    CLPBK$     Topics

Under normal DDE, this would be viewed as:

   SERVER NAME       APPLICATION       TOPIC     ITEM
   \\machine-name    Clipsrv           System     Topics

This will return a list of SHARED "objects" in the ClipBook. Now that you have a list of objects, the next step is to query the types of formats available. For example, assume that "$Test" was returned as an object. To find a list of formats, start a new conversation with ClipBook with the following parameters:

   APPLICATION             TOPIC           ITEM
   \\machine-name\NDDE$    $Test           FormatList

This will return a list of the formats, each starting with the "&" symbol (for example, CF_TEXT will return "&Text").

Using the object name and format type, it is possible to make a connection to the server and return the contents of the topic. The last set of parameters is:

   APPLICATION             TOPIC           ITEM
   \\machine-name\NDDE$    $Test           &Text

If your application wants to share information via NetDDE, use the ClipBook program or call one of the NetDDE application programming interfaces (APIs), which will create an entry in the [DDEShares] section of SYSTEM.INI. This procedure allows other users to access your information.

Additional reference words: 3.10
KBCategory: kbprg kbwebcontent
KBSubcategory: UsrNetDde

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Last reviewed: August 5, 1996
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