How to Focus "Nothing"

Try this sample (code + form).
The panel will receive the focus (see "edit -> exit" output in the memo).
Use TDBEdit instead of TEdit.
ic

------ code (unti1.pas) ------

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Panel1: TPanel;
    Edit1: TEdit;
    SpeedButton1: TSpeedButton;
    Memo1: TMemo;
    procedure SpeedButton1Click(Sender: TObject);
    procedure Edit1Exit(Sender: TObject);
    procedure Panel1Enter(Sender: TObject);
    procedure Edit1Enter(Sender: TObject);
    procedure Panel1Exit(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.SpeedButton1Click(Sender: TObject);
begin
  Form1.SetFocusedControl(Panel1);
end;

procedure TForm1.Edit1Exit(Sender: TObject);
begin
  Memo1.Lines.Add('edit -> exit');
end;

procedure TForm1.Panel1Enter(Sender: TObject);
begin
  Memo1.Lines.Add('panel2 -> Enter');
end;

procedure TForm1.Edit1Enter(Sender: TObject);
begin
  Memo1.Lines.Add('edit -> Enter');
end;

procedure TForm1.Panel1Exit(Sender: TObject);
begin
  Memo1.Lines.Add('panel -> exit');
end;

end.

------ form (unit1.dfm) ------

object Form1: TForm1
  Left = 192
  Top = 107
  Width = 314
  Height = 202
  Caption = 'Form1'
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'MS Sans Serif'
  Font.Style = []
  OldCreateOrder = False
  PixelsPerInch = 96
  TextHeight = 13
  object Panel1: TPanel
    Left = 8
    Top = 16
    Width = 185
    Height = 41
    Caption = 'Panel1'
    TabOrder = 0
    OnEnter = Panel1Enter
    OnExit = Panel1Exit
    object SpeedButton1: TSpeedButton
      Left = 138
      Top = 11
      Width = 23
      Height = 22
      OnClick = SpeedButton1Click
    end
    object Edit1: TEdit
      Tag = 1
      Left = 8
      Top = 12
      Width = 121
      Height = 21
      TabOrder = 0
      Text = 'Edit1'
      OnEnter = Edit1Enter
      OnExit = Edit1Exit
    end
  end
  object Memo1: TMemo
    Left = 8
    Top = 80
    Width = 185
    Height = 73
    Lines.Strings = (
      'Memo1')
    TabOrder = 1
  end
end

BTW, TSpeedButton cannot receive focus because it is not a TWinControl descendant.
ic

Thanks illusion_Chaser:

Yes, I know that I could Call SetFocus for an arbitrary Control in the form. The problem is that I have lots of forms with lots of buttons, and doing it manually can lead to error if I forget to implement it just once. That's why I want to build a component.

I could make the new component search for "any" other component in the form and just focus that but I hardly think that's an elegant solution (besides there's the posibility that there are no more "Focusable" controls).

thanx esoftbg:

The reason I use SpeedButtons is beause of its "Flat" property. Beause of the graphic design, the hability to be "transparent" is needed.

Is there a way to make a "focusable" button transparent?

...That is, Is there a way to make a "focusable" button, THAT ACCEPTS BITMAPS, transparent?

There is a
TJvTransparentButton
JEDI VCL

Sorry, it is not 'focusable'.

ok, I got another solution...
Look at TNewSpeedButton class.

------ code (unit1.pas) -------

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, Buttons, StdCtrls, ExtCtrls, Mask, DBCtrls;

type
  TForm1 = class(TForm)
    Memo1: TMemo;
    DBEdit1: TDBEdit;
    procedure FormDestroy(Sender: TObject);
    procedure DBEdit1Enter(Sender: TObject);
    procedure DBEdit1Exit(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure FormShow(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

TNewSpeedButton = class(TSpeedButton)
private
  pnl: TPanel;
public
  procedure MyOnClick(Sender: TObject);
  constructor Create(AOwner: TComponent); override;
  destructor Destroy; override;
end;


var
  Form1: TForm1;

implementation

{$R *.dfm}

var
  myBtn: TNewSpeedButton;

procedure TForm1.FormDestroy(Sender: TObject);
begin
  FreeAndNil(myBtn);
end;

{ TNewSpeedButton }

constructor TNewSpeedButton.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);

  OnClick := MyOnClick; //bind OnClick event

  pnl := TPanel.Create(AOwner);
  pnl.Parent := (AOwner as TForm);
  pnl.SetBounds(0, 0, 1, 1);
  pnl.Visible := True;
end;

destructor TNewSpeedButton.Destroy;
begin
  FreeAndNil(pnl);
  inherited;
end;

procedure TNewSpeedButton.MyOnClick(Sender: TObject);
begin
  pnl.SetFocus;
end;

procedure TForm1.DBEdit1Enter(Sender: TObject);
begin
  Memo1.Lines.Add('edit -> enter');
end;

procedure TForm1.DBEdit1Exit(Sender: TObject);
begin
  Memo1.Lines.Add('edit -> exit');
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  myBtn := TNewSpeedButton.Create(Self);
  myBtn.Parent := Self;
  myBtn.SetBounds(250, 30, 20, 20);
  myBtn.Visible := True;
end;

procedure TForm1.FormShow(Sender: TObject);
begin
  DBEdit1.SetFocus;
end;

end.

------ form (unit1.dfm) -------

object Form1: TForm1
  Left = 192
  Top = 107
  Width = 314
  Height = 202
  Caption = 'Form1'
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'MS Sans Serif'
  Font.Style = []
  OldCreateOrder = False
  OnCreate = FormCreate
  OnDestroy = FormDestroy
  PixelsPerInch = 96
  TextHeight = 13
  object Memo1: TMemo
    Left = 8
    Top = 48
    Width = 185
    Height = 73
    Lines.Strings = (
      'Memo1')
    TabOrder = 1
  end
  object DBEdit1: TDBEdit
    Left = 8
    Top = 12
    Width = 121
    Height = 21
    TabOrder = 0
    OnEnter = DBEdit1Enter
    OnExit = DBEdit1Exit
  end
end

changing all the buttons is more work than calling a proc
anyway you can just call ActiveControl:=nil; :)
you can also do this in your descendant component

something like:



unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Edit1: TEdit;
    procedure FormCreate(Sender: TObject);
    procedure Edit1Exit(Sender: TObject);
  private
    Button: TSpeedButton;
  public
    { Public declarations }
  end;

  TMySPB = class(TSpeedButton)
  protected
    procedure Click; override;
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

{ TMySPB }

procedure TMySPB.Click;
var
  LCtl: TControl;
begin
  inherited;
  LCtl:=Parent;
  while Assigned(LCtl) and Assigned(LCtl.Parent) do
    LCtl:=LCtl.Parent;
  if LCtl is TCustomForm then
    TCustomForm(LCtl).ActiveControl:=nil;
end;

procedure TForm1.Edit1Exit(Sender: TObject);
begin
  caption:='out';
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  Button:=TMySPB.Create(Self);
  Button.Parent:=Self;
  Button.SetBounds(16, 48, 84, 25);
  Button.Caption:='unfocus control';
end;

end.

I tried it but I couldn't make it to work. It seems that the OnExit event (and its correspondent message) only gets called when the focus is changes from one control to ANOTHER.

Can I send the message of "Exit" to the current ActiveControl? Something like this:

   ActiveControl.ReceiveWindowsMessage(WM_COMPONENT_EXIT);

Or something like that?

Yes! I just found it:

function Perform(Msg: Cardinal; WParam, LParam: Longint): Longint;

WM_COMPONENT_EXIT? nothing... I was just describing what i would LIKE...

however, I've found the right message name: CM_EXIT

The only thing I need is a way of converting a HWND to a TControl, then I can get the focused Handle, typecast it as a TControl and call the Perform method.

Do you gyus know how?

I meant, typecast a HWND into a "TWinControl", not into a "TControl", sorry

Nevermind, I dont need it I could just work with the handle directly.

For the record this the final solution is to call on the click method of the TSpeedBtn:

  SendMessage(windows.GetFocus, CM_EXIT, 0 ,0);

what about SendMessage(DBEdit1.Handle, CM_EXIT, 0 ,0); ?

why using a specific control when it should be generic ?