CODEWITHSUNDEEP
delphisendmessage
hikari
hikari

Reputation: 3503

Delphi: Send message to running instance of same app, without any TForm

I'd like to know a way to do the following:

App starts, no forms created. 2nd App instance starts, it detects one instance is already running (this is sorted already)

I want 2nd instance to send the 1st one a message, without using BROADCAST; Id like a way to find a handle to the 1st instance to send it the message directly.

The 1st instance must have a class name to be found with that the 2nd one hasn't yet created, so that it won't send the message to itself.

How would I use FindWindow in this scenario? How do I create a window-less class/object identifiable by FindWindow?

Upvotes: 0

Views: 1378

Answers (3)

Remy Lebeau
Remy Lebeau

Reputation: 595467

You can send messages to the TApplication window if you know the value of its Title property. The sending instance can temporarily set its own Title to a different value so as not to confuse FindWindow(). The receiving instance can use the TApplication.OnMessage event or TApplication.HookMainWindow() method to receive the message.

Upvotes: 1

alzaimar
alzaimar

Reputation: 4622

You could use shared memory to pass data. See this article for details

Upvotes: 1

MBo
MBo

Reputation: 80127

You can not find windowless object by means of FindWindow.

But you can create invisible window with AllocateHWnd function - see TTimer source as example. Use SetWindowText to set title for easy searching

Upvotes: 2

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