TWinControl.Focused Method

Determines whether the control has input focus.

Pascal

function Focused: Boolean; dynamic;

C++

__fastcall Boolean Focused();

Description

Use the Focused method to see if the control is the active control. When Focused returns true, the control has the input focus. If Focused returns false, the user cannot interact with the control.

C++ Examples:

Copy Code

/*
This example uses the OnActiveControlChange event to detect
when focus changes on the form. When focus changes, the hint
for the active control is displayed on the status bar. To use
this example, you must add a status bar to the form and set 
its SimplePanel property to true.  Add a new public procedure,
ActiveControlChanged, to the TForm1 class declaration.
*/
void _fastcall TForm1::ActiveControlChanged(System::TObject *Sender)
{
  TWinControl *Active = NULL;
  for (int I = 0; I < Form1->ControlCount; I++)
  {
    TWinControl *Temp = dynamic_cast<TWinControl *>(Form1->Controls[I]);
    if (Temp && Temp->Focused())
      Active = Temp;
  }
  if ((Active != NULL) && (Active->Hint != ""))
    StatusBar2->SimpleText = GetLongHint(Active->Hint) + " focus";
}

void __fastcall TForm1::MouseOverChanged(TObject *Sender)
{
  TWinControl *Active = dynamic_cast<TWinControl *>(Sender);
  if (Active != NULL)
    StatusBar1->SimpleText = GetLongHint(Active->Hint) + " mouse over";
}

/*
Assign this method as the OnActiveControlChange event
handler by setting it from the form's OnCreate event handler:
*/
void __fastcall TForm1::FormCreate(TObject *Sender)
{
  Screen->OnActiveControlChange = ActiveControlChanged;
}

/*
Make sure you clean up the screen object when the form is
freed by adding this OnDestroy event handler to the form:
*/
void __fastcall TForm1::FormDestroy(TObject *Sender)
{
  Screen->OnActiveControlChange = 0;
}

Delphi Examples:

Copy Code

{
This example uses the OnActiveControlChange event to detect
when focus changes on the form. When focus changes, the hint
for the active control is displayed on the status bar. To use
this example, you must add a status bar to the form and set 
its SimplePanel property to true.  Add a new public procedure,
ActiveControlChanged, to the TForm1 class declaration.
}

type
  TForm1 = class(TForm)
    StatusBar1, StatusBar2: TStatusBar;
    Button1: TButton;
    RadioButton1: TRadioButton;
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
    procedure MouseOverChanged(Sender: TObject);
  private
    { Private declarations }
  public
    procedure ActiveControlChanged(Sender: TObject);
  end;

var
  Active : TWinControl;
  I: Integer;
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.ActiveControlChanged(Sender: TObject);
var
  Active : TWinControl;
  I: Integer;
begin
  Active := nil;
  for I:= 0 to ControlCount -1 do
  begin
    if (Controls[I] is TWinControl) then
      if (Controls[I] as TWinControl).Focused then
        Active := TWinControl(Controls[I]);
  end;
  if ((Active <> nil) and (Active.Hint <> '')) then
  begin
    StatusBar2.SimpleText := GetLongHint(Active.Hint) + ' focus';
  end
end;

procedure TForm1.MouseOverChanged(Sender: TObject);
var
  Active : TWinControl;
  I: Integer;
begin
  if (Sender is TWinControl) then
  begin
    Active := TWinControl(Sender);
    StatusBar1.SimpleText := GetLongHint(Active.Hint) + ' mouse over';
  end;
end;

{
Assign this method as the OnActiveControlChange event
handler by setting it from the form's OnCreate event handler:
}
procedure TForm1.FormCreate(Sender: TObject);
begin
  Screen.OnActiveControlChange := ActiveControlChanged;
end;

{
Make sure you clean up the screen object when the form is
freed by adding this OnDestroy event handler to the form:
}
procedure TForm1.FormDestroy(Sender: TObject);
begin
  Screen.OnActiveControlChange := nil;
end;