DDE and application initialisation time

Question

Our application is DDE enabled. It acts as a server. It has its own file type, and offers an 'Open' command.

When launching application from a right-click on a saved file (ie reading HKEY_CLASSES_ROOT-----\shell etc) we sometimes get "there was a problem sending the command to the program". Especially win10.

On problem PCs we test a VBA script that triggers our exe, waits a second, and then sends DDE commands. This works well.

We conclude we need a pause, or to increase timeout on the DDE conversation.

Can this be done? Is there a globally effective registry setting? Any ideas?

Answer 1

No, you cannot pause or increase the DDE timeout.

Instead, you should look at possible problems with your application. It is likely that your program is starting to pump messages before your DDE server is up and running. As soon as you start handling messages, Windows assumes your DDE server is running. So, it sends you the message, but your server is not up to receive it yet. Make sure that no thread in the program is handling Windows messages before the DDE server is setup.