Delphi 6转义键不工作

Question

我在主应用程序中遇到了一个奇怪的问题，即捕获转义键。我创建了一个简单的测试表单来查看可能出现的问题，因为按escape键之前是工作的。到目前为止，它仍然不能工作，我不知道为什么。

unit Unit1;
interface
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;
type
  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    procedure Button1KeyDown(Sender: TObject; var Key: Word;
      Shift: TShiftState);
    procedure Button2KeyDown(Sender: TObject; var Key: Word;
      Shift: TShiftState);
    procedure FormKeyDown(Sender: TObject; var Key: Word;
      Shift: TShiftState);
    procedure Button1Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
    procedure OnAppMessage(var Msg: TMsg; var Handled: Boolean);
  public
    { Public declarations }
  end;
var
  Form1: TForm1;
implementation
{$R *.dfm}
procedure TForm1.OnAppMessage(var Msg: TMsg; var Handled: Boolean);
begin
  if Msg.message = WM_KeyDown then
    showmessage('MSG');
end;
procedure TForm1.Button1KeyDown(Sender: TObject; var Key: Word;
  Shift: TShiftState);
begin
  if key = VK_ESCAPE then
    showmessage('ESC');
end;
procedure TForm1.Button2KeyDown(Sender: TObject; var Key: Word;
  Shift: TShiftState);
begin
  if key = VK_ESCAPE then
    showmessage('ESC');
end;
procedure TForm1.FormKeyDown(Sender: TObject; var Key: Word;
  Shift: TShiftState);
begin
  if key = vk_escape then
    Button1Click(sender);
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
  showmessage('Button1Click');
end;
procedure TForm1.FormCreate(Sender: TObject);
begin
  Application.OnMessage := OnAppMessage;
  button1.Cancel := True; // set at design time as well
  self.KeyPreview := True; // set at design time as well
end;
end.

由于某些原因，当按escape时，它不会在我在button1中放置的点上断开。OnKeyDown或甚至应用程序消息WM_KEYDOWN——所有其他键在这里断开。我测试了我的键盘，只是为了确保这个键能正常工作，而且很好。

是否有什么可能导致这个或我做错了?

谢谢。

Answer 1

将此添加到组件的类中:

procedure HandleDlgCode(var Msg:TMessage); message WM_GETDLGCODE;

，然后在实现部分:

procedure TComponentClass.HandleDlgCode(var Msg:TMessage);
var
  M: PMsg;
begin
  Msg.Result := DLGC_WANTALLKEYS or DLGC_WANTESCAPE or DLGC_WANTCHARS or DLGC_HASSETSEL;
  if Msg.lParam <> 0 then
    begin
      M := PMsg(Msg.lParam);
      case M.message of
        WM_KEYESCAPE, WM_CHAR:
        begin
          Perform(M.message, M.wParam, M.lParam);
          Msg.Result := Msg.Result or DLGC_WANTMESSAGE;
        end;
      end;
    end
  else
    Msg.Result := Msg
end;

Answer 2

这是因为您将Button1的Cancel属性设置为True。注释行:

button1.Cancel := True;

，您将能够捕获转义键。

Answer 3

尝试重新启动。