Category: Windows
Title: Send a windows message with SendMessage
Date added: 15.03.2006
Hits: 4558

{
  This is useful if you want to send a message from your DLL back
  to the calling application.
}
const
  MY_MESSAGE = WM_USER + 4242;
 
type
  TForm1 = class(TForm)
    Button1: TButton;
    
procedure Button1Click(Sender: TObject);
    // Handler that receive the Message
    
procedure MessageReceiver(var msg: TMessage); message MY_MESSAGE;
  end;
var
  Form1: TForm1;
implementation
{$R *.DFM}

procedure TForm1.Button1Click(Sender: TObject);
var
  txt: string;
begin
  txt := 'Hello World';
  SendMessage(Form1.Handle, MY_MESSAGE, 0, DWORD(PChar(txt)));
end;

procedure TForm1.MessageReceiver(var msg: TMessage);
var
  txt: PChar;
begin
  txt := PChar(msg.lParam);
  msg.Result := 1;
  ShowMessage(txt);
end;
end.

1. How to hide a program from the taskbar? (2086 Hits)

2. How to restart the own program? (3200 Hits)

3. How to show the find folder dialog? (1459 Hits)

4. How to change size of the Windows Start Button? (2131 Hits)

5. How to simulate the pressing of keyboard keys? (12001 Hits)

For any problems or recommendations about Delphi Tricks site, please

feel free to contact us on that e-mail: support@delphitricks.com.
If you want to advertise on the site use that e-mail: advertise@delphitricks.com.

You can freely use or modify these Delphi source codes for non-commercial use. We are not responsible of any damages that can be caused by the utilisation of that source codes.