asked on

How do I trap an event in another application?

I would like to detect when the user executes e.g. a CTRL-C (Copy) command in another application.

When this happens I would like my Delphi application to take control and allow the user to Paste the
information into a Delphi Edit field.

ASKER CERTIFIED SOLUTION

GoodTimes

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GoodTimes

oops, sorry, forget the WH_CBT. Only use WH_KEYBOARD.

Omri

rondi

Don't forget to put all your hookin code in a DLL

Mohammed Nasman

Hello

do you want to hook the events or the clipboard, if you want to spy the clipboard, so if any one press ctrl+c or press copy from the menu, you will get that in ur delphi application, here's a program

unit Unit1;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;

type
TForm1 = class(TForm)
Memo1: TMemo;
procedure FormCreate(Sender: TObject);
procedure FormDestroy(Sender: TObject);
private
procedure WMDrawClipboard(var Msg: TMessage);
message WM_DRAWCLIPBOARD;
procedure WMChangeCBChain(var Msg: TMessage);
message WM_CHANGECBCHAIN;

public
end;

var
Form1: TForm1;
NextInChain : THandle;

implementation

uses ClipBrd;

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
begin
NextInChain := SetClipboardViewer(Handle);
end;

procedure TForm1.WMDrawClipboard(var Msg:TMessage);
begin
if Clipboard.HasFormat(cf_text) then begin
Memo1.Lines.Clear;
Memo1.PasteFromClipboard
end else begin
//do something with other clipboard formats
end;
//pass the message on to the next window
if NextInChain <> 0 then
SendMessage(NextInChain, WM_DrawClipboard, 0, 0)
end;

procedure TForm1.WMChangeCBChain(var Msg: TMessage);
var
Remove, Next: THandle;
begin
Remove := Msg.WParam;
Next := Msg.LParam;
with Msg do
if NextInChain = Remove then
NextInChain := Next
else if NextInChain <> 0 then
SendMessage(NextInChain, WM_ChangeCBChain,
Remove, Next)
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
ChangeClipboardChain(Handle, NextInChain);
end;

end.

I hope that what u need

Mohammed

bjornborg

ASKER

Thank you Mohammed,
Your example works fine, but I guess I have to use the SetWindowsHookEx within a DLL as Omri suggested in order to "stop" the current application and transfer the control to the Delphi application.

After having seen the comment/answer from Omri, I have searched for more information about "SetWindowsHookEx" and have found the answer to "Global hooks" which has a detailed and long answer with example application and DLL.

Thanks
Bj?rn

bjornborg

ASKER

The answer points to the routine that must be used, but does not provide solution example (and/or could have pointed to existing example in database)