RegisterHotKeys in Delphi App - have I done it right?

Posted on 2009-04-11
Last Modified: 2012-05-06
I have an application for which I want to implement user definable HotKeys for a number of procedures.  I've used the RegisterHotKeys methods in a procedure that can be called with true to register them, false to unregister.

The HotKey sequences are stored in the applications registry and applied to the HotKeys through the use of an integer array.

I want to be a good neighbor to other applications that may be running, so I wanted my HotKeys active only when my app has focus.  So I call the HotKeys(true) in an application.OnActivate event and turn them off in an Application.OnDeactivate event.

Now, if the user chooses to assign something to. for instance, Control-S,  everything seems to be working properly.  When my app has focus, Control-S does what it is supposed to do, but if WordPad, for instance, is focused, Control-S does the proper file save operation.

So what I've done seems to work, But I made all this up myself and I know from sad experience that just because I can make something work doesn't mean I've done it right.  Is what I've done the best way to do this?  Is there a more proper way?  Am I being a good neighbor?

In the main form class methods section:
    procedure AppOnActivate(Sender: TObject);
    procedure AppDeActivate(Sender: TObject);
In public:
   procedure HotKey(onoff: boolean);
in private
    kid4 : Integer;
    procedure WMHotKey(var Msg: TWMHotKey); message WM_HOTKEY;
In OnCreate procedure for Main form
Definitions of procedures:
procedure T_form.WMHotKey(var Msg: TWMHotKey);
  if Msg.HotKey = kid4 then ToggleInOut;
procedure T_form.HotKeys(onoff: Boolean);
if onoff then
     kid4 := GlobalAddAtom('hk3');
     BK[3]:=RegisterHotKey(Handle, kid4, HK[3,0]+HK[3,1],HK[3,2]);
  end else
    UnRegisterHotKey(Handle, kid4);
procedure T_form.AppOnActivate(Sender: TObject);
procedure T_form.AppDeActivate(Sender: Tobject);

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Question by:DMTrump
  • 4
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LVL 22

Accepted Solution

8080_Diver earned 500 total points
ID: 24123590
Man!  I CONGRATULATE you on your professionalism!  What you've done is excellent!
The only thing I can think of to improve on your user friendliness and neighborliness to other applicationswould be to store the user's hot-key settings in a database.
You are absolutely being a good neighbor and the way you are doing this is really cool!

Author Comment

ID: 24123663
Thanks for the compliment - I ought to award you the points just for capitalizing CONGRATULATE - but I will wait a little bit just to make sure someone doesn't come up with a reason to point out that we're both mistaken! <LOL>

55 years ago I was out hunting with a friend.  As we climbed a fence I handed him my 22 and while I was climbing the fence he shot himself in the foot with MY rifle!  It wasn't until I got into programming some 20 years later that I started shooting MYSELF in the foot!  So I just thought I'd check to make sure the gun wasn't loaded.

I considered using a database, but there will only be 20 or so HotKeys and I can store them all in a single string in the Registry and only have to parse the string once into the integer array.

Author Comment

ID: 24123679
8080 Diver,

Great handle - makes me guess that you also are a rather "Senior" programmer!   I used to program embedded systems built on 8080s!

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LVL 37

Expert Comment

by:Geert Gruwez
ID: 24124334
nice, to finish it off, you could create a component from it ...

Author Comment

ID: 24124428
I believe I will do that -  Not terribly high on my todo list - but when I get it done I'll come back to this thread and post it here as a comment.  Since some of my products are programmers tools I've been creating a few things to distribute as freeware to attract attention to my commercial products.  This will be a nice one to add.  Thanks to both of you for confirmation.

Author Closing Comment

ID: 31569218
Thanks for the evaluation.   I hope I've explained it well enough to make this thread useful to others.  Someday soon I'll turn the technique into a component.
LVL 37

Expert Comment

by:Geert Gruwez
ID: 24124869
well, supplying a link to your website in your profile would help

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