德尔福 - 检测同时按下3个键

Question

我想检测我的表单中的3个按键,例如Ctrl+ C+ N...我需要检测的键入的表单将始终以Ctrl两个字母开头.

我怎么做的？

Answer 1

当其中一个键到达时,您可以查看其他键是否已经关闭.例如:

procedure TForm1.FormKeyDown(Sender: TObject; var Key: Word;
  Shift: TShiftState);
begin
  if Shift = [ssCtrl] then begin
    case Key of
      Ord('C'):
        if (GetKeyState(Ord('N')) and $80) = $80 then
          ShowMessage('combo');
      Ord('N'):
        if (GetKeyState(Ord('C')) and $80) = $80 then
          ShowMessage('combo');
    end;
  end;
end;

然而,这也将检测例如N+ Ctrl+ C,一个不以Ctrl密钥开头的序列.如果这不符合有效的密钥组合,您可以借助标记保留一些密钥历史记录.以下应仅检测最初以下列开头的序列Ctrl:

type
  TForm1 = class(TForm)
    procedure FormKeyDown(Sender: TObject; var Key: Word; Shift: TShiftState);
    procedure FormKeyUp(Sender: TObject; var Key: Word; Shift: TShiftState);
  private
    FValidKeyCombo: Boolean;
  end;

...

procedure TForm1.FormKeyDown(Sender: TObject; var Key: Word;
  Shift: TShiftState);
begin
  if FValidKeyCombo and (Shift = [ssCtrl]) then
    case Key of
      Ord('C'):
        if (GetKeyState(Ord('N')) and $80) = $80 then
          ShowMessage('combo');
      Ord('N'):
        if (GetKeyState(Ord('C')) and $80) = $80 then
          ShowMessage('combo');
    end;
  FValidKeyCombo := (Shift = [ssCtrl]) and (Key in [Ord('C'), Ord('N')]);
end;

procedure TForm1.FormKeyUp(Sender: TObject; var Key: Word; Shift: TShiftState);
begin
  FValidKeyCombo := False;
end;