学习 Message(14): 区分左右 Shift、Ctrl、Alt

代码文件:

---

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Memo1: TMemo;
    procedure FormCreate(Sender: TObject);
    procedure FormMouseDown(Sender: TObject; Button: TMouseButton;
      Shift: TShiftState; X, Y: Integer);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
begin
  Memo1.Align := alLeft;
  Memo1.ScrollBars := ssVertical;
  Memo1.Clear;
end;

procedure TForm1.FormMouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  if GetKeyState(VK_SHIFT)  < 0 then Memo1.Lines.Add('Shift');
  if GetKeyState(VK_LSHIFT) < 0 then Memo1.Lines.Add('LeftShift');
  if GetKeyState(VK_RSHIFT) < 0 then Memo1.Lines.Add('RightShift');

  if GetKeyState(VK_CONTROL)  < 0 then Memo1.Lines.Add('Ctrl');
  if GetKeyState(VK_LCONTROL) < 0 then Memo1.Lines.Add('LeftCtrl');
  if GetKeyState(VK_RCONTROL) < 0 then Memo1.Lines.Add('RightCtrl');

  if GetKeyState(VK_MENU)  < 0 then Memo1.Lines.Add('Alt');
  if GetKeyState(VK_LMENU) < 0 then Memo1.Lines.Add('LeftAlt');
  if GetKeyState(VK_RMENU) < 0 then Memo1.Lines.Add('RightAlt');

  Memo1.Lines.Add('');
end;

end.

窗体文件:

---

object Form1: TForm1
  Left = 0
  Top = 0
  Caption = 'Form1'
  ClientHeight = 206
  ClientWidth = 339
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  OnCreate = FormCreate
  OnMouseDown = FormMouseDown
  PixelsPerInch = 96
  TextHeight = 13
  object Memo1: TMemo
    Left = 80
    Top = 80
    Width = 185
    Height = 89
    Lines.Strings = (
      'Memo1')
    TabOrder = 0
  end
end