INF: WM_DDE_EXECUTE Message Must Be Posted to a Window

ID Number: Q77842

3.00

WINDOWS

Summary:

Chapter 15 of the "Microsoft Windows Software Development Kit

Reference, Volume 2" documents the dynamic data exchange (DDE)

protocol. The following statement is found on page 15-2:

An application calls the SendMessage function to issue the

WM_DDE_INITIATE message or a WM_DDE_ACK message sent in response to

WM_DDE_INITIATE. All other messages are sent using the PostMessage

function.

In the book "Windows 3: A Developer's Guide" by Jeffrey M. Richter (M

& T Computer Books), the sample setup program uses the SendMessage

function to send itself a WM_DDE_EXECUTE message that violates the DDE

protocol and may not work in future versions of Windows.

More Information:

In Richter's sample, no real DDE conversation exists. The correct

method to achieve the desired result is to use the SendMessage

function to send a user-defined message to the window procedure. When

this message is processed, proceed accordingly. For more information on

user-defined messages, see chapter 6 of the "Microsoft Windows Software

Development Kit Reference, Volume 1."

Additional reference words: 3.00