• Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 443
  • Last Modified:

route OnKeyPress event to procedure

hi experts, i would like to route all TWinControl control's OnKeyPress event to my local procedure as follow. why it's error "undeclared identifier: 'OnKeyPress' ? isn't TWinControl the base class of this event ?

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Edit1: TEdit;
    Button1: TButton;
    procedure FormCreate(Sender: TObject);
  private
    procedure ev_OnKeyPress(Sender: TObject; var Key: Char);
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.FormCreate(Sender: TObject);
var
  wc : TWinControl;
  t : TList;
  i : Integer;
begin
  t := TList.Create;
  try
    t.Add(Edit1);
    t.Add(Button1);
    for i := 0 to t.Count -1 do
      TWinControl(t[i]).OnKeyPress := ev_OnKeyPress;
  finally
    t.Free;
    t := nil;
  end;
end;
procedure TForm1.ev_OnKeyPress(Sender: TObject; var Key: Char);
begin

end;

end.
0
Explorer060599
Asked:
Explorer060599
  • 2
1 Solution
 
DragonSlayerCommented:
Nope, you can't... OnKeyPress is a property that is in the Protected section of the hierarchy, until it reached the last level, e.g. TEdit, TButton, etc.

So you might have to do this

if (t[i] is TEdit) then
  TEdit(t[i]).OnKeyPress := ev_OnKeyPress
else ...



HTH
DragonSlayer
0
 
DragonSlayerCommented:
or unless you cheat... :)

code this in the beginning of your programme

type
  THackedWinControl = TWinControl;

and later in your code:

for i := 0 to t.Count - 1 do
  THackedWinControl(t[i]).OnKeyPress := ev_OnKeyPress;
0
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

Join & Write a Comment

Featured Post

Cloud Class® Course: MCSA MCSE Windows Server 2012

This course teaches how to install and configure Windows Server 2012 R2.  It is the first step on your path to becoming a Microsoft Certified Solutions Expert (MCSE).

  • 2
Tackle projects and never again get stuck behind a technical roadblock.
Join Now