Solved

route OnKeyPress event to procedure

Posted on 2002-05-28
2
437 Views
Last Modified: 2012-05-11
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
Comment
Question by:Explorer060599
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
2 Comments
 
LVL 14

Expert Comment

by:DragonSlayer
ID: 7041130
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
 
LVL 14

Accepted Solution

by:
DragonSlayer earned 50 total points
ID: 7041133
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

Featured Post

Industry Leaders: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Introduction The parallel port is a very commonly known port, it was widely used to connect a printer to the PC, if you look at the back of your computer, for those who don't have newer computers, there will be a port with 25 pins and a small print…
Introduction I have seen many questions in this Delphi topic area where queries in threads are needed or suggested. I know bumped into a similar need. This article will address some of the concepts when dealing with a multithreaded delphi database…
In this video, viewers will be given step by step instructions on adjusting mouse, pointer and cursor visibility in Microsoft Windows 10. The video seeks to educate those who are struggling with the new Windows 10 Graphical User Interface. Change Cu…
Michael from AdRem Software explains how to view the most utilized and worst performing nodes in your network, by accessing the Top Charts view in NetCrunch network monitor (https://www.adremsoft.com/). Top Charts is a view in which you can set seve…
Suggested Courses
Course of the Month11 days, 15 hours left to enroll

623 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question