Passwort Char umgangen

[jziersch]

Hier der code einer einfachen aber sicheren Passwort Eingabekomponente.
Da es nicht von TEdit abstammt kann man es auch nichts auslesen.

Code:

type
  TWPGeheim = class(TCustomControl)
  private
    FText : String;
  protected
    procedure CreateParams(var Params: TCreateParams); override;
    procedure MouseDown(Button: TMouseButton; Shift: TShiftState;X, Y: Integer); override;
  public
    procedure Paint; override;
    procedure KeyPress(var Key: Char); override;
    property  Text : String read FText write FText;
  end;

{ TWPGeheim }

procedure TWPGeheim.KeyPress(var Key: Char);
begin
  if Key=#8 then FText := Copy(FText,1,Length(FText)-1)
  else if Key>#32 then FText := FText + Key;
  invalidate;
end;

procedure TWPGeheim.MouseDown(Button: TMouseButton; Shift: TShiftState; X,
  Y: Integer);
begin
  inherited;
  SetFocus;
end;

procedure TWPGeheim.Paint;
var s : string;
    i : Integer;
begin
  inherited;
  if Focused then
       Canvas.Font.Color := clHighlight
  else Canvas.Font.Color := clWindowText;
  SetLength(s, Length(FText));
  for I := 1 to Length(s) do s[i] := '*';
  Canvas.TextOut( 1,1,s);
end;

procedure TWPGeheim.CreateParams(var Params: TCreateParams);
begin
  inherited CreateParams(Params);
  Params.Style := Params.Style or WS_BORDER or WS_TABSTOP;
end;

Kann man natürlich erweitern, z.b. um CTRL+V für Einfügen zu unterstützen:

Code:

procedure TWPGeheim.KeyPress(var Key: Char);
begin
  if Key=#8 then FText := Copy(FText,1,Length(FText)-1)
  else if Key>#32 then FText := FText + Key
  else if Key=Char(22) then // ^V
  begin
    Clipboard.Open;
    try
     SetLength(FText,30);
     SetLength(FText,Clipboard.GetTextBuf(PChar(FText),30));
    finally
     Clipboard.Close;
    end;
  end;
  invalidate;
end;