TButton + VK_Return - delphi

Question

Here I have reproduced situation I have encounter couple of times. I have two forms. Form1 and Form2. Form1 has one edit field and OnKeyup event hooked up. Form2 has only one button and OnClick hooked up. When in Form1 user press VK_Retrun in field of type TEdit, Form2.Show is executed. Form2 shows up with focus on the button. The event OnClick is hooked up with the code "Close" inside. If user hit VK_RETURN key on the keyboard, Form2 closes as expected.. but here come the problem, Form2 got fired straight up again. It seems as when Form1 get focus the key is still in "a queue" and the edit field will proceed with VK_RETURN.
Here is a full listings of this situation:
unit UTestButton;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;
type
TForm1 = class(TForm)
Edit1: TEdit;
procedure Edit1KeyUp(Sender: TObject; var Key: Word;
Shift: TShiftState);
private
{ Private declarations }
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
uses UTestButton2;
{$R *.dfm}
procedure TForm1.Edit1KeyUp(Sender: TObject; var Key: Word;
Shift: TShiftState);
begin
if (Key = VK_Return) THEN
Form2.Show;
end;
end.
This is the second unit.
unit UTestButton2;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;
type
TForm2 = class(TForm)
Button1: TButton;
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
var
Form2: TForm2;
implementation
{$R *.dfm}
procedure TForm2.Button1Click(Sender: TObject);
begin
Close;
end;
end.
In praxes I use sometimes simple form with labels or informations but one or two buttons and focus on button. User can hit key on keyboard as expected. If he use the vk_return and the underlying control use the key, I have to do some workaround to clear keys of buffer as with
PeekMessage(Mgs, 0, WM_CHAR, WM_CHAR, PM_REMOVE);
That´s not totally satisfying for me. Has anyone solution for this situation?

Answer 1

Simply handle the OnKeyDown event instead of OnKeyUp for your initial edit box:
procedure TForm1.Edit1KeyDown(Sender: TObject; var Key: Word;
Shift: TShiftState);
begin
if (Key = VK_RETURN) then
Form2.Show;
end;