{
MessageDlg example
This example uses a button on a form. When the user clicks the button, a message box appears, asking if the user wants to exit the application. If the user chooses Yes, another dialog box appears informing the user the application is about to end. When user chooses OK, the application ends.
} 
procedure TForm1.Button1Click(Sender: TObject);
begin
  if MessageDlg('Welcome to my Delphi application.  Exit now?',
    mtConfirmation, [mbYes, mbNo], 0, mbYes) = mrYes then
  begin
    MessageDlg('Exiting the Delphi application.', mtInformation,
      [mbOk], 0, mbOk);
    Close;
  end;
end; 
