检测Shift、Alt和Ctrl键

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Label1: TLabel;
    procedure FormKeyDown(Sender: TObject; var Key: Word; Shift: TShiftState);
    procedure FormMouseDown(Sender: TObject; Button: TMouseButton;
      Shift: TShiftState; X, Y: Integer);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.FormKeyDown(Sender: TObject; var Key: Word;
  Shift: TShiftState);
begin
  if Shift >= [ssShift] then
    label1.Caption := '你按下了Shift键';
  if Shift >= [ssAlt] then
    label1.Caption := '你按下了Alt键';
  if Shift >= [ssCtrl] then
    label1.Caption := '你按下了Ctrl键';
end;

procedure TForm1.FormMouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  if Shift >= [ssLeft] then
    label1.Caption := '你单击鼠标左键';
  if Shift >= [ssMiddle] then
    label1.Caption := '你单击鼠标中键';
  if Shift >= [ssDouble] then
    label1.Caption := '你双击了鼠标';
  if ssRight in Shift then
    label1.Caption := '你单击鼠标右键';
end;

end.