Mega Code Archive
Register a systemwide hotkey
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Title: register a systemwide hotkey?
{
The following example demonstrates registering hotkeys with the
system to globally trap keys.
Das Folgende Beispiel zeigt, wie man Hotkeys registrieren und
darauf reagieren kann, wenn sie gedr ckt werden. (systemweit)
}
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms,
Dialogs;
type
TForm1 = class(TForm)
procedure FormCreate(Sender: TObject);
procedure FormDestroy(Sender: TObject);
private
{ Private declarations }
id1, id2, id3, id4: Integer;
procedure WMHotKey(var Msg: TWMHotKey); message WM_HOTKEY;
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
// Trap Hotkey Messages
procedure TForm1.WMHotKey(var Msg: TWMHotKey);
begin
if Msg.HotKey = id1 then
ShowMessage('Ctrl + A pressed !');
if Msg.HotKey = id2 then
ShowMessage('Ctrl + Alt + R pressed !');
if Msg.HotKey = id3 then
ShowMessage('Win + F4 pressed !');
if Msg.HotKey = id4 then
ShowMessage('Print Screen pressed !');
end;
procedure TForm1.FormCreate(Sender: TObject);
// Different Constants from Windows.pas
const
MOD_ALT = 1;
MOD_CONTROL = 2;
MOD_SHIFT = 4;
MOD_WIN = 8;
VK_A = $41;
VK_R = $52;
VK_F4 = $73;
begin
// Register Hotkey Ctrl + A
id1 := GlobalAddAtom('Hotkey1');
RegisterHotKey(Handle, id1, MOD_CONTROL, VK_A);
// Register Hotkey Ctrl + Alt + R
id2 := GlobalAddAtom('Hotkey2');
RegisterHotKey(Handle, id2, MOD_CONTROL + MOD_Alt, VK_R);
// Register Hotkey Win + F4
id3 := GlobalAddAtom('Hotkey3');
RegisterHotKey(Handle, id3, MOD_WIN, VK_F4);
// Globally trap the Windows system key "PrintScreen"
id4 := GlobalAddAtom('Hotkey4');
RegisterHotKey(Handle, id4, 0, VK_SNAPSHOT);
end;
// Unregister the Hotkeys
procedure TForm1.FormDestroy(Sender: TObject);
begin
UnRegisterHotKey(Handle, id1);
GlobalDeleteAtom(id1);
UnRegisterHotKey(Handle, id2);
GlobalDeleteAtom(id2);
UnRegisterHotKey(Handle, id3);
GlobalDeleteAtom(id3);
UnRegisterHotKey(Handle, id4);
GlobalDeleteAtom(id4);
end;
end.
{
RegisterHotKey fails if the keystrokes specified for the hot key have
already been registered by another hot key.
Windows NT4 and Windows 2000/XP: The F12 key is reserved for use by the
debugger at all times, so it should not be registered as a hot key. Even
when you are not debugging an application, F12 is reserved in case a
kernel-mode debugger or a just-in-time debugger is resident.
}
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